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THE  INTERNATIONAL  SCIENTIFIC  SERIES 
VOLUME   LXVI 


THE 

INTERNATIONAL  SCIENTIFIC  SERIES. 


Each  book  complete  in  One  Volnme,  12mo,  and  bound  in  Cloth. 


1.  THE  FORMS  OF  WATER  IN  CLOUDS  AND  RIVERS,  ICE  AND  GLA- 

CIERS.   By  J.  Tykdall,  LL.  D.,  F.  R.  S.    With  35  Illustrations.    SI -50. 

2.  PHYSICS  AND  POLITICS  ;   or,  Thoughts  on  the  Application  of  the  Prin- 

ciples   of  "Natural   Selection"  and   "Inheritance"  to  Political  Society. 
By  Walter  Bagehot.    S1»50. 

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trations.   $1.75. 

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2  The  International  Scientific  xSéric-s.— (Continued.) 


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sity of  Halle.    With  91  Illustrations.    %\rih. 

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fessor Pietko  Blaserna,  Royal  University  of  Rome.     With  numerous 
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bia College.     With  130  Hlustrations.     $2.00. 

27.  THE  HUMAN  SPECIES.    By  Professor  A.  de  Quateefages,  Museum  of 

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30.  ANIiLlL  LIFE  AS  AFFECTED  BY  THE  NATURAL  CONDITIONS  OF 

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31.  SIGHT  :  An  Expo.«ition  of  the  Principles  of  Monocular  and  Binocular  Vision. 

By  Professor  Joseph  Le   Conte,  LL.D.,  University  of  California.    With 
132  Illustrations.    §1.50. 

32.  GEN-ERAL  PHYSIOLOGY  OF  MUSCLES  AND  NERVES.    By  Professor 

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33.  ILLUSIONS  :  A  Psychological  Study.    By  Jasies  Sitllt.    §1.50. 

34  THE  SUN.    By  Professor  C.  A.  Yocng,  College  of  New  Jersey.    With  83 
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35.  VOLCANOES  ;  What  they  Are  and  What  they  Teach.    By  Professor  John 

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36.  SUICIDE  :  An  Essay  in  Comparative  Moral  Statistics.    By  Prof  essor  Heney 

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S1.75. 

37.  THE  FORMATION  OF  VEGETABLE  MOULD,  THROUGH  THE  AC- 

TION OF  WORMS.      With  Observations  on  their  Habits.      By  Chaeles 
Daewin,  LL.D.,  F.  R.  S.     With  15  Illustrations.    $1.50. 


The  International  Scientific  Series. — (Continued.) 


88.  THE  CONCEPTS  AND  THEORIES    OF  MODERN  PHYSICS.    By  J.  B. 

Stallo.     S1.75. 

39.  THE   BRAIN  AND  ITS   FUNCTIONS.    By  J.   LuTS,  Hospice  Salpêtrière, 

Paris.    With  6  Illustrations.    $1-50. 

40.  MYTH  AND  SCIENCE.     By  Tito  Vignoli.     §1.50. 

41.  DISEASES  OF  MEMORY  :  An  Essay  in  the  Positive  Psychology.    By  Th. 

RiBOT,  author  of  "  Heredity."'     §1.50. 

42.  ANTS,  BEES.  AND  WASPS.     A  Record  of  Observations  of  the  Habits  of 

the  Social  Hymenoptera.    By  Sir  John  Lubbock,  Bart.,  F.  R.  S.,  etc.   $2.00. 

43.  THE  SCIENCE  OF  POLITICS.    By  Professor  Sheldox  A^ios.    Sl-TS. 

44.  ANIMAL  INTELLIGENCE.    By  George  J.  Rohaxes,  M.  D.,  F.  R.  S.  §1.75. 

45.  MAN  BEFORE  METALS.    By  Professor  N.  Jolt,  Science  Faculty  of  Tou- 

louse.   With  148  Illustrations.    §1.75. 

46.  THE    ORGANS    OF    SPEECH    AND    THEIR   APPLICATION    IN    THE 

FORMATION   OF  ARTICULATE    SOUNDS.      By  Professor  G.  H.  voN 
Meter,  University  of  Zurich.     With  47  Illustrations.    §1.75. 

47.  FALLACIES  :  A  View  of  Logic  from  the    Practical  Side.      By   Alfred 

Sidgwick,  B.  a.,  Oxon.     §1.75. 

48.  ORIGIN  OF  CULTIVATED  PLANTS.    By  Alphonse  de  Candolle.   §2.00. 

49.  JELLY-FISH,   STAR-FISH,  AND  SEA-URCHINS.    A  Research  on  Primi- 

tive Nervous  Systems.     By  George  J,  Ro3Iaxes,  M.  D.,  F.  R.  S.    With  63 
Hlustrations.    §1.75. 

50.  THE  COMMON  SENSE  OF  THE  EXACT  SCIENCES.    By  William  King- 

Dox  Clifford.    With  100  Figures.    §1.50. 

51.  PHYSICAL  EXPRESSION  :  Its  Modes  and  Principles.    By  Fraxcis  War- 

NER,  M.D.,  Assistant  Physician.  London  Hospital.    With  51  Elu«trations 
S1.75. 

52.  ANTHROPOID   APES.     By  Professor  Robert  Hartmann    University  of 

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53.  THE  MAMMALIA  IN  THEIR  RELATION  TO  PRIMEVAL  TOIES.    By 

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54.  COMPARATIVE  LITERATURE.     By  Professor  H.  M.  Posnett,  M.  A.,  Uni- 

versity College,  Auckland.     §1.75. 

5.5.  EARTHQUAKES  AND  OTHER  EARTH  MOVEMENTS.  By  Professor  John 
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56.  :inCROBES,  FERMENTS,  AND  MOULDS.    By  E.  L.  Trouessart.    With 

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57.  THE  GEOGRAPHICAL  ANT)   GEOLOGICAL   DISTRIBUTION  OF  ANI- 

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58.  WEATHER.    A  Popular  Exposition  of  the  Nature  of  Weather  Changes  from 

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The  International  Scientific  xS'me*.— (Continued.) 


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60.  INTERNATIONAL  LAW,  with  Materials  for  a  Code  of  International  Law. 

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62.  ANTHROPOLOGY.    An  Introduction  to  the  Study  of  Man  and  Civilization. 

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64.  THE  SENSES,  INSTINCTS,  AND  INTELLIGENCE  OF  ANIMALS,  WITH 

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By  Dr.  C.  N.  Starcke,  University  of  Copenhagen.    $1.75. 

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68.  SOCIALISM  :  New  and  Old.    By  Professor  Wllliam  Graham,  M.  A.,  Queen's 

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vard  University.    Illustrated.    $1.50. 

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New  York  :   D.  APPLETOX  &  CO.,  72  Fifth  Avenue. 


THE   INTERNATIONAL  SCIENTIFIC  SERIES 


PHYSIOLO  GY     OF 
BODILY    EXERCISE 


BY 

FERN  AND   LAGRANGE,    M.  D; 


NEW    YORK 
D.    APPLETON    AND    COMPANY 

1898 


ijL3 


CONTENTS. 


PART     I. 
MUSCULAR   WORK. 

THE     ORGANS     OF     WORK — MOVEMENTS — HEAT — 
COMBUSTION. 

Chapter  I.— The  Organs  of  Movement.  ...  3 
Exercise  and  Work— Muscle— Nerve  ;  Avalanche  Theory— 
The  Spinal  Cord;  Reflex  Actions;  Unconscious  Movements— 
The  Brain;  Reflex  Movements;  Voluntary  Movements — The 
Motor  Centres;  associated  Muscular  Actions  —  The  Will, 
Agent  of  Work— Muscular  Contraction— Course  of  a  Volun- 
tary Stimulus;  INIode  of  Transmission — Nervous  Vibration  and 
the   Muscular  Wave— Time  of  Transmission;  Latent  Period. 

Chapter  II. — Movements 20 

Associated  action  of  different  Regions  during  Work — How  a 
Blow  is  given  with  the  Fist— Co-Ordination  of  Movements; 
Antagonistic  Muscles;  the  Muscular  Sense— Ataxic  patients — 
Static  Contraction — Stiffness  in  Exercise— Muscular  Education 
—Association  of  the  great  Organic  Functions  with  Muscular 
Movement— £^^r/— The  Porter  and  his  Load— Effort  during 
slight  Expenditure  of  Force:— T^^  //ar^  «  A'z//- Frequency 
of  Effort  in  Exercise— Long  Distance  and  Sprint  Running 
— Influence  of  Movements  on  the  Circulation— The  Quicken- 
ing of  the  Pulse;  its  Mechanism— The  Pulmonar}'  Circulation 
and  the  Active  Congestion  of  the  Lungs— Congestion  of  the 
Brain  during  Movement — Dancing  Dervishes— A  Runaway 
Horse. 

Chapter  III.— Heat 33 

The  Human  Motor  and  Heat  Engines  —  The  Mechanical 
Equivalent  of  Heat— Heat  is  a  Cause  of  Movement,  not  its 
Effect— Heat  Lost— How  the  Temperature  of  the  Body  is 
Regulated  —  Effects  of  Heat  on  Muscle  —  Experiment  of 
Marey  on  Caoutchouc — Observation  of  Daily  Phenomena — 
Muscle  Heated  and  Muscle  Numbed  by  Cold— Gestures  of 
Anger— Why  we  Make  preliminary  Passes  in  Fencing— The 
Hare  which  has  just  been  put  up— Effects  of  too  high  a 
Temperature — Death  of  Muscle  at  -|-  45°  C. 


VI  CONTENTS. 

Chapter  IV. — Combustion  .  42 

General  Idea  of  Combustion — Chemical  Sources  of  Heat — 
Ancient  and  Modern  Theories — Part  played  by  Oxygen — 
Oxidation;  Hydration;  Decomposition — Complexity  of  the 
Chemical  phenomena  which  produce  Heat  —  Combustible 
Materials;  Food  Stuffs;  Reserve- Materials;  Tissue-Materials 
— Results  of  Combustion  —  Products  of  Dissimilation  — 
Products  of  Incomplete  Oxidation;  Uric  Acid — Elimination  of 
Products  of  Dissimilation — Eliminating  Organs — Auto- Intoxi- 
cation— Dangers  of  Human  Miasma. 


PART    II. 

FATIGUE. 

LOCAL  FATIGUE  —  BREATHLESSNESS  — STIFFNESS  — 
OVERWORK — EXHAUSTION — THEORY  OF  FATIGUE 
— REPOSE. 

Chapter  I. — Local  Fatigue 57 

Experimental  Fatigue — Absolute  and  Relative  Fatigue — Fatigue 
in  Ordinary  Conditions  of  Work;  it  is  always  Relative — 
Examples  of  Relative  and  of  Absolute  Fatigue — Causes  of 
Sensation  of  Fatigue — Causes  of  Muscular  Powerlessness 
— Influence  of  Waste-Products  of  Combustion;  Transmission 
of  Fatigue  to  Muscles  which  have  not  been  Working— Use  of 
Fatigue — Part  played  by  the  Brain  in  Fatigue — Unconscious 
Movements  cause  less  Fatigue  than  Voluntary  Movements; 
Practical  consequences. 

Chapter  II.— Breathlessness 67 

A  Hard  Run — Exercises  which  cause  Loss  of  Breath  ;  Trotting 
and  Galloping  ;  Going  Upstairs — Law  of  Breathlessness — 
Respiratory  Need;  Conditions  under  which  it  Increases  and 
Diminishes — Carbonic  Acid  ;  Its  Production  Increases  with 
Muscular  Activity  ;  it  Diminishes  during  Repose — The  Sleep 
of  the  Marmot — Explanation  of  the  Law  of  Breathlessness 
— Why  we  lose  Breath  in  Running  —  Why  the  Horse 
Gallops  with  its  Lungs — Why  Exercises  of  the  Legs  cause 
more  Loss  of  Breath  than  those  of  the  Arms — The  Coefficient 
of  Breathlessness — The  Horse  which  exceeds  its  Paces — 
Breathlessness  is  an  Auto- Intoxication  by  Carbonic  Acid — 
Analogy  with  Asphyxia — Impossibihty  of  Fighting  against 
Breathlessness. 


CONTENTS.  vii 

Chapter  III. — Breathlessness  {continued)  ...  86 
Mechanism  of  Breathlessness — Reflex  Disturbances  of  the  Re- 
spiratory Movements  —  Physical  Sensations  and  Moral  Im- 
pressions—  Stani)neri7ig  Respiration — Why  we  become  less 
Breathless  at  a  Fencing-School  than  in  a  Duel — Reflexes  due 
to  Carbonic  Acid — Reflexes  are  at  first  Useful;  They  become 
Dangerous  when  Exaggerated — Dangers  of  Instinctive  Move- 
ments— Part  played  by  the  Heart  in  Breathlessness — 
Active  Congestions — Fatigue  of  the  Heart-Muscle  and  Passive 
Congestion  of  the  Lungs — The  Influence  of  the  Heart  is 
Serondaiy — Cessation  of  Breathlessness  notwithstanding  the 
Persister  ce  of  Circulatory  Disturbances  after  Exercise — 
Personal  Observation  :  the  Ascent  of  Canigou — Effort  ;  its 
part  in  Breathlessness — Prompt  Advent  of  Breathlessness 
in  Wrestling — Sprint  Running  and  Long  Distance  Running 
■ — Our  observations  on  the  Rhythm  of  Respiration  During 
Breathlessness  —  Inequality  of  Expiration  and  Inspiration 
during  Breathlessness; — Causes  of  this  Inequality  —  Grave 
Phenomena  of  Breathlessness — Action  of  Caibonic  Acid  on 
the  Muscular  Fibres  of  the  Heart. 

Chapter  IV. — Breathlessness  {concluded)  .  .  .103 
Three  Stages  of  Breathlessness — First  or  Salutary  Stage—- 
Respiration  more  Active,  but  not  Insufficient — Second  Stage — 
Symptoms  of  slight  Carbonic  Acid  Intoxication;  Leaden  Com- 
plexion ;  Breathless  Respiration  ;  General  Discomforts — Third 
or  Asphyxiai  Stage — Cerebral  Disturbances  ;  Symptoms  of 
severe  Carbonic  Acid  Intoxication;  Vertigo;  Unconscious 
Movements;  Syncope;  Stoppage  of  the  Heart — Observations 
— Dangers  of  Running  as  a  Sport — Too  vigorous  an  Assault- 
at-Arms — Animals  succumbing  to  Breathlessness;  the  Horse 
ridden  to  Death — Death  of  a  Carrier  Pigeon — A  Hunted 
Beast  which  Breaks  Cover. 

Chapter  V. — Stiffness       . in 

Return  to  the  Gymnasium;  a  Sleepless  Night — Febrile  Stiffness 
— Three  Degrees  of  Stiffness  of  Fatigue— Causes  of  Stiffness; 
Immunity  due  to  Habituation — Explanation  of  Symptoms — ■ 
Imperfection  of  Theories — Local  Symptoms;  They  are  due 
to  Trauina — General  Symptoms;  Tfiey  are  due  to  an  Auto- 
intoxication —  Deposits  of  Urates  —  Influence  of  Muscular 
Exercise  on  their  Formation  ;  Diversity  of  opinions  of 
Authors  —  Personal  Observations  —  Conditions  which  cause 
Variations  in  the  Formation  of  Deposits  after  Work — Slow 
appearance  of  the  Deposits  after  Exercise. — Influence  of 
the  Intensity  of  the  Work  on  their  Formation  —  Hitherto 
misunderstood  influence  of  Training — Constant  Correlation 
observed  between  the  Production  of  Stiffness  and  the 
Formation  of  Deposits — This  Correlation  is  found  in  all 
circumstances  which  render  the  Individual  more  liable  to 
Fatigue — Influence  of  Moral  Causes  on  Consecutive  Fatigue 
and  on  the  Deposits. 


Vlll  CONTENTS. 

Chapter  VI. — Stiffness  {concluded)  .        .        .        .  125 

Objection  to  Our  Theory — Are  Urinary  Deposits  due  to  the 
Perspiration  produced  by  Exercise?— Observations  opposed 
to  the  opinion  of  Authors  on  this  Subject — An  Experiment 
in  Fatigue  :  Rowing-  from  Limoges  to  Paimbœuf — Agreement 
of  Observations  with  Chemical  Analysis — Exercise  produces 
a  Uricaemic  condition — Analogy  of  Stiffness  of  Fatigue 
with  certain  Febrile  conditions — Stiffness  of  Fatigue  and  an 
Attack  of  Gout — Cause  of  Immunity  from  Stiffness  when  in 
Training  — •  Function  of  Reserve  Materials  —  Products  of 
Dissimilation  —  Part  played  by  Uric  Acid  in  Stiffness  — 
Stiffness  is  an  Auto- Intoxication. 

Chapter  VII. — Overwork 134 

Overwork  is  Exaggerated  Fatigue — Different  forms  of  Over- 
Work — Acute  Overwork  ;  Death  from  Breathlessness — Sub- 
acute Overwork — The  Stag  hunted  to  Death — P^orced  Game; 
Rapid  Cadaveric  Rigidity;  Prompt  Putrefaction — Mechanism 
of  Death  by  sub-acuie  Overwork — Auto- Intoxication  by  pro- 
ducts of  Dissmiilaiion — Extractives,  Lactic  Acid — Discoveries 
of  Gautier;  Poisons  of  Living  Organisms;  Leucomaines — Rarity 
of  sub-acute  Overwork  in  Man — The  Soldier  of  Marathon 
— Observations  on  rapid  Cadaveric  Rigidity  in  Men  Dying  in 
a  condition  of  Overwork — Curious  positions  of  the  bodies; 
Horror-stricken  Expressions  in  Persons  who  have  been 
Assassinated  —  Effects  of  Overwork  on  the  Flesh  of 
Animals — Dangers  of  Eating  Overworked  Flesh — Culinaiy 
Qualities  given  to  Flesh  in  certain  cases  by  Overwork — 
Sufïering  a  cause  of  Overwork  —  Cruelty  of  a  Butcher — 
Chronic  Overwork  the  form  most  frequently  observed  in 
Man. 

Chapter  VIII. — Overwork  {continued)      .        .       .        .145 

The  Disorders  of  Overwork — Pseudo-Typhoid  Fevers — Auto- 
infection  dcaà.  Auto-Typhisation — Opinion  of  Professor  Peter 
— Microbes  and  Leucomaines — Frequency  of  Fevers  of  Over- 
work— Greater  predisposition  of  Adolescents —Two  personal 
Observations — Abuse  of  Fencing  and  too  much  of  the  Trapeze 
— Overwork  in  the  Army — Too  Energetic  a  Colonel — Forced 
Manœuvres — Overwork  a  cause  aggravating  Disease — Infec- 
tive forms  assumed  by  the  mildest  Disorders  in  Overworked 
systems — So-called  Sunstroke  of  Soldiers  on  the  March — The 
large  influence  of  Overwork  in  the  production  of  these  Dis- 
orders— Rarity  of  Sunstroke  in  Horse-Soldiers;  its  frequency 
in  Foot- Soldiers — Spares  persons  habituated  to  Fatigue- 
Rarity  of  Sunstroke  in  Harvest  Men. 


CONTENTS.  ïX 

Chapter  IX.— Overwork  (concludeif)  .  .  .  .153 
A  Phthisical  Hercules  —  The  Over-trained  Horse  —  Chronic 
Overwork — Exhaustion  through  using  up  of  the  Organic 
Tissues — Difference  betv^'een  the  Physiological  Processes  of 
Acute  and  of  Chronic  Overwork  —  Auto-i?itoxicaiion  and 
AutofJiagy — Dangers  of  excessive  Expenditure  —  Defective 
Balance  "between  Expenditure  and  Income. — Impoverishment 
of  the  System  by  excessive  work — Atrophy  and  Degeneration 
of  Muscles — The  Calves  of  Runners — Overwork  of  the  Heart- 
Muscle — The  Overdriven  Heart — Nervous  Forms  of  Over- 
work— Anosmia  of  the  Nerve-Centres  and  Exhaustion  of  the 
Nervous  Substance — Epilepsy  of  Walkers — Observations  on 
Peasants — Insanity  from  Overwork;  Influence  of  Harvest-time 
on  its  Frequency — Frequency  of  Neuroses  in  Overworked 
Peasants. 

Chapter  X.— The  Theory  of  Fatigue  .  .  .  .163 
Fatigue  is  a  Regulator  of  Work— Organic  Conditions  which 
hasten  the  onset  of  the  Sensation  of  Fatigue;  Weakness  of 
the  Organs;  Excess  of  Reserve  Materials — Order  and  con- 
nection of  the  Phenomena  of  Fatigue — Local  and  General 
Fatigue;  Immediate  and  Consecutive  Fatigue — The  different 
Processes  of  Fatigue  : — (i)  Traumatic  Effects  of  Work  on  the 
Motor  Organs — (2)  Auto-Intoxication  by  the  Products  of  Dis- 
similation— (3)  Urga?iic  Exhaustion  through  Autophagy — (4) 
Dynamic  Exhaustion  through  Expenditure  of  all  the  Force  at 
the  Disposal  of  the  Muscular  and  Nervous  Elements— In- 
sufficiency of  existing  Physiological  ideas  for  explaining  all 
the  Phenomena  of  Fatigue. 

Chapter  XI.— Repose 170 

Repair  of  the  Animal  Machine— Cleansing  of  the  Organs  ; 
Elimination  of  the  Waste-Products  of  Combustions — Duninu- 
tion  of  Combustions  during  Repose — Fall  of  Temperature  and 
Depression  of  Vital  Functions  during  Sleep — The  Duration  of 
Repose  must  vary  according  to  the  Form  of  Fatigue — Short 
Period  of  Repose  necessary  to  dissipate  Breathlessness — 
The  Runners  of  Tunis— Difference  in  the  Rapidity  of  Elimi- 
nation of  the  various  Products  of  Dissimilation — Dynamic 
Effects  of  Repose;  they  are  still  unexplained— Influence  of 
Periods  of  Repose  in  relation  to  the  Conservation  of  Energy 
— The  English  Boxers. 


CONTENTS. 


PART     III. 

HABITUATION  TO  WORK. 

POWER     OF    RESISTING    FATIGUE — MODIFICATION      OF 

ORGANS     BY     WORK — MODIFICATION   OF   FUNCTIONS 

OF   THE    TISSUES   BY  WORK — TRAINING. 

Chapter  I. — Power  of  Resisting  Fatigue  .  .  .181 
Variability  in  the  Power  of  Resisting  Fatigue — Effects  of  In- 
action—Eiïects  of  Habitual  Activity — Different  Mode  of  Life 
causes  Different  Conformation  ;  Frugivorous  Animals  and 
Hunting  Animals;  the  Flesh  of  the  Hare  and  the  Flesh  of  the 
Wolf — The  Labourer  and  the  Scholar — How  we  must  explain 
"Habituation  "  to  Work. 

Chapter  H. — Modification  of  the  Organs  by  Work.  187 
Function  nr-akes  Structure — Disappearance  of  Organs  when 
their  Function  has  Ceased  ;  Maintenance  of  Organs  by  Per- 
sistence of  Function — Why  gymnasts  remain  supple  even  in 
Old  Age — Modification  of  Motor  Organs  by  Exercise — Modi- 
fication of  Organic  Apparatus  associated  with  Movement  ; 
Amplification  of  the  Lungs — Changes  in  the  Living  Tissues 
due  to  Work — More  active  Assimilation;  Growth  of  Muscles — 
More  rapid  Dissimilation  ;  Diminution  of  Reserve  Materials 
— Increase  of  Strength  through  Growth  of  the  Muscular 
Tissues — Lessening  of  Fatigue;  it  is  due  to  the  gradual  Dis- 
appearance of  the  Reserve  Materials — How  this  Result  is 
Explained — Fat  causes  Breathlessness — By  what  Mechan- 
ism? Insufficiency  of  admitted  Explanations  —  Theory  of 
Trainers  :  the  "  Internal  Fat."  Objections  to  this  Theory 
^•Reserve  Fat  and  Constitutional  Fat — Fat  Runners — Easy 
Dissimilation  of  Reserve-Fats,  causes  Breathlessness  by 
Excessive  Production  of  Carbonic  Acid — Reserve  Proteids 
and  Consecutive  Fatigue  —  Disappearance  of  Stiffness  of 
Fatigue  in  Connection  with  the  Disappearance  of  Urinary 
Deposits  after  Exercise — Personal  Observations  on  Fatigue. 

Chapter  III. — Modification  of  Functions  by  Work  .  199 
Increase  in  the  Contractile  Force  of  Muscle — Probable  increase 
in  the  Power  of  Conduction  of  Nerves.  Improvement  in  the 
Faculties  of  Co-Ordination  of  Movement — Education  of  the 
Muscular  Sense — Domination  of  Reflex  Actions  by  the  Will; 
Regulation  of  the  Respiratory  Movements— -Changes  produced 
in    the    Nervous    System    by    Muscular    Exercise — Material 


CONTENTS.  xi 

Changes  in  the  Nen^ous  Tissues  ;  are  they  purely  Hypo- 
thetical ? — An  observation  of  Luys —  Functional  Changes  in 
the  Nervous  System — The  Memory  of  the  Spinal  Cord;  its 
Use  in  the  Performance  of  often  Repeated  Actions — Psychical 
Modifications  due  to  Habituation  to  Work — Skill — PhysicaJ 
Courage — Incredible  Energy  of  Prize-fighters. 

Chapter  IV. — Training 210 

Various  meanings  of  the  word  Tramtng — Training,  as  we 
understand  it  here,  is  the  Adaptation  of  the  Organism  to 
Work — Natural  Training  and  Methodical  Training — Methods 
of  Training  ;  rarely  put  in  force  in  France  ;  ver}'  widely 
Practised  in  England — Training  of  Boxers  —  Training  of 
Oarsmen — A  Specimen  of  Method — Physiological  explanation 
of  the  Phenomena.  The  Loss  of  Weight  ;  Diet  ;  Care  of  the 
Skin — Capital  Importance  of  ISIuscular  Work  in  Training — 
Temperament  of  the  Trained  Man — Advantages  and  Dis- 
advantages of  his  Condition. 


PART     IV. 

THE  DIFFERENT  EXERCISES. 

PHYSIOLOGICAL  CLASSIFICATION  OF  EXERCISES  — 
VIOLENT  EXERCISES — EXERCISES  OF  STRENGTH — 
EXERCISES  OF  SPEED — EXERCISES  OF  ENDURANCE 
— MECHANISM   OF   DIFFERENT   EXERCISES. 

Chapter     I.  —  Physiological     Classication     of     Bodily 
Exercises  .........    227 

Quantity  of  Work  Done  in  an  Exercise — Gentle,  Moderate,  and 
Violent  Exercises — Quality  of  Work  in  Exercise — Exercises  of 
Strength,  of  Speed,  and  of  Endurance — ^Mechanism  of  the 
various  Exercises. 

Chapter  II. — Violent  Exercises 230 

Violent  Exercise  must  not  be  confounded  with  Fatiguing 
Exercise — Difficulty  of  appreciating  the  Quantity  of  Work 
expended  in  an  Exercise — Difficult  Movements — Feats  of 
Strength  —  Gymnastic  Pedants  —  Children's  Games  ami 
G>Tnnastics — Skipping  compared  with  Climbing  a  Rope — 
Analysis  of  Exercises — How  the  Physiological  Effects  of 
Work  may  indicate  its  Degree  of  Intensity. 

Chapter  HI. — Exercises  of  Strength  ....    236 

Gymnastics — Frequent    Intervention  of  Effort  in   Exercises   of 

Strength — Why    it  is    impossible  to   have    "a   Smile  on    the 

Lips''  in  practising  an  Exercise  of  btiength — Charles  Bell  on 


Xll  CONTENTS. 

the  Facial  Movements — Intensity  of  Breathlessness  in  Ex- 
ercises of  Strength — ^Wrestling — Advantages  of  Exercises  of 
Strength — Their  superiority  to  Exercises  of  Speed  for  In- 
creasing the  size  of  the  Body — Inconvenience  of  Exercise  of 
Strength  —  Danger  of  Effort  ;  Frequency  of  Hernia  ; 
Frequency  of  Kupture  of  Blood- Vessels — Overwork  and 
Exhaustion  in  Forced  Labours. 

Chapter  IV. — Exercises  of  Speed 244 

Accumulation  of  Work  by  the  rapid  Succession  of  Movements — 
Common  results  of  works  of  Strength  and  Exercises  of 
Speed;  the  "Thirst  for  Air";  Breathlessness — Strength  and 
Speed  combined  —  "Forced"  Exercise;  its  Dangers  —  Part 
played  by  the  Nervous  System  in  Exercises  of  Speed — Law  of 
Helmholtz;  the  Loss  of  Time  in  Muscle;  "  Latent  Period" — 
Irritability  of  Muscle  ;  its  part  in  Exercises  of  Speed  ;  its 
Variability  in  different  Kinds  of  Animals  :  the  Snail  and  the 
Bird  —  Its  Variability  in  different  Individuals  and  different 
Nations  :  Dutch  Rowers — Effects  of  Exercises  of  Speed — • 
Effects  due  to  the  Accumulation  of  Work  ;  they  resemble 
the  Effects  of  Exercises  of  Strength — Effects  due  to  Expendi- 
ture of  Nervous  Energy  ;  resulting  Influence  on  Nutrition 
— Why  these  Exercises  cause  Loss  of  Weight. 

Chapter  V. — Exercises  of  Endurance.  .  .  .  257 
Conditions  of  Exercise  of  Endurance  ;  Moderation  of  Efforts  ; 
Slow  Repetition — Fractional  Work — Conditions  Inherent  in 
the  Worker— Men  and  Animals  who  have  "Staying  Power" 
— Need  for  perfect  Equilibrium  between  the  Intensity  of  the 
Work  and  the  Power  of  Resistance  of  the  System  —  Im- 
portance of  Respiration  in  regulating  Exercises  of  Endurance — 
Exercise  of  Endurance  makes  the  Functions  more  Active  with- 
out Fatiguing  the  Organs — Association  of  the  Great  Functions 
with  Moderate  and  Prolonged  Muscular  Work;  Respiration 
more  Active  without  Breathlessness;  Circulation  Quickened 
without  Palpitation — Indications  and  Contra-indications  for 
Exercises  of  Endurance — Parallel  with  Exercises  of  Speed 
• — Why  Children  bear  Exercises  of  Endurance  badly — 
Veterans  and  Conscripts. 

Chapter  VI. — Mechanism  of  Different  Exercises  .  270 
The  Principal  Action  and  the  Indirect  Actions  m  Exercise — Part 
played  by  each  Part  of  the  Body  in  the  Chief  Exercises — 
Office  of  the  Upper  Limbs — Gymnastic  Apparatus  ;  especially 
bring  the  Arms  into  Action — Suspejision  and  Support  of  the 
Body — Breasting  and  Circling  in  the  Gymnasium — Rowing; 
Fencing  ;  Single-Stick  ;  English  Boxing  ;  Dumb- Bells — 
Office  of  the  Lower  Limbs — Walking  and  Running;  French 
Boxing  or  Chausson — Usefulness  of  Exercises  of  the  Legs  ia 


CONTENTS.  Xlîi 

developing  the  Chest — Office  of  the  Pelvis — Flexion  of  Pelvis 
on  Thorax  in  Gymnastic  Exercises — Development  thus  given 
to  the  Abdominal  Muscles  —  The  best  '"Girdle  against 
Obesity" — Office  of  the  Vertebral  Column  in  Exercise  — 
Importance  of  Position — The  Horseman  with  a  "Good  Seat" 
• — Active  Share  of  the  Vertebral  Column  in  Exercise — Thrust 
from  the  Loins — Leaping  —  Passive  Share  of  the  Vertebral 
Column  in  Exercise — Orthopaedic  Effects  of  Attitudes  of 
"  Suspension  " — Swedish  Gymnastics. 


PART     V. 

THE  RESULTS  OF  EXERCISE. 

GENERAL  EFFECTS  OF  EXERCISE — EXERCISES  WHICH 
DEVELOP  THE  CHEST — LOCAL  EFFECTS  OF  EXER- 
CISE— EXERCISES  WHICH  PRODUCE  DEFORMITY^ 
EXERCISES  WHICH   DO   NOT  PRODUCE  DEFORMITY. 

Chapter  I. — General  Effects  of  Exercise.       .       .    285 

Varying  Nature  of  the  Effects  of  Exercise — Its  two  Chief  Re- 
sults, the  Losses  and  the  Gains — Increased  Activity  of  Com- 
bustions; Resulting  in  the  Using  Up  of  the  Reserve  INIaterials 
— Why  is  Nutrition  more  Active?  Part  played  by  Oxygen 
— The  "Need  for  Exercise";  to  What  it  is  Due — Accumu- 
lation of  Reserve  IMaterials — Sluggish  Nutrition — Why  an 
Inactive  Man  "  Fears  Fatigue  "  —  Insufficient  Exercise  — 
Unwholesome  Effects  on  Nutrition  —  Slackening  of  the 
Process  of  Dissimilation — Obesity — Deficient  Oxidation  and 
Excess  of  Reserve  Materials.  Incomplete  Oxidations — Gout 
— Necessity  for  Exercise — Effects  Common  to  all  Forms  of 
Muscular  Work — Special  Effects  according  to  the  Quality  of 
the  Work — Observation  on  Horses — Trotting  and  Walking. 

Chapter  II.— Exercises  which  Develop  the  Chest  .  297 
Importance  of  Oxygen  in  Nutrition — Advantages  of  a  great 
Development  of  the  Chest — How  this  Result  can  be  obtained 
by  Exercise  —  Received  Opinions  on  this  Subject — Our 
Reasons  against  them — By  what  Mechanism  the  Chest  is 
Developed  —  Forced  Breathing  —  Pressure  from  within  out- 
wards— Increased  Breadth  of  the  Shoulders  not  to  be  Confused 
with  Increased  Size  of  the  Chest — Conditions  which  Develop 
the  Chest — Amphtude  cf  the  Respiratory  Movements- 
Opening  out  of  the  Pulmonary  Air-Cells — Increase  of  the 
Respiratory  Need— The  Chest  of  Mountaineers— Exercises 
which  produce  a  "Thirst  for  Air"  —  Exercises  suitable  for 
Developing  the  Chest  —  An  unexpected  conclusion:  Superi- 
ority of  Exercises  of  the  Legs  to  those  of  the  Arms- 
Running  and  Skipping. 
2 


XIV  CONTENTS. 

Chapter  IIT.— Local  Effects  of  Exercise  .  .  .  306 
Effects  on  neighbouring  parts  —Useful  Effects  :  Compression  of 
Vessels  by  the  Contracting  Muscles  ;  Quickening  of  the  Cir- 
culation as  a  result — Disappearance  of  Œdema  during 
Exercise  —  Injurious  Effects  of  Muscular  Contraction  : 
Excessive  Compression  of  Internal  Organs  —  Dangers  of 
Effort— 'K^QCts  of  Work  on  Muscle — Useful  Effects  :  Increase 
in  Size — Injurious  Effects  :  Wasting  of  the  Organ  through 
Excessive  Work — The  Accidents  of  Work — Muscular  Ruptures 
— Tendency  of  Muscular  Fibre  to  Shorten  through  Ex- 
cessive Work — Semi-flexion  of  the  Fore-arm  in  Gymnasts — 
Dangers  of  Muscular  Contractures — How  Deviations  of  the 
Spine  are  produced  by  Ill-planned  Exercise. 

Chapter  IV.— Exercises  which  Produce  Deformity     314 

Gymnastics  and  ^Esthetics — A  rooted  Prejudice,  the  Beauty  of 
Form  of  Gymnasts — Deformities  due  to  Gymnastics  with 
Apparatus — Mechanism  of  these — Too  much  Exercise  of 
the  Arms — Attitudes  of  Support — Breasting — The  Horizon- 
tal Bar — The  Parallel  Bars — Circli7tg — The  Trapeze — The 
Round  Back  of  Gymnasts — Fencing  —  "Fencers'  Scoliosis." 
—  Comparative  Observations  on  Right-Handed  and  Left- 
Handed  Fencers — Our  conclusions  are  opposed  to  those 
of  former  authors — Opinion  of  Bouvier  and  Boulland— 
Mechanism  of  these  Deformities— Different  attitudes  of  the 
Fencer  during  the  different  Stages  of  a  Fencing- Bout — 
Guard,  Attack,  Parry  and  Thrust — Dumb-Bells — Ridings 
Different  Effects  of  Riding  in  a  Race  and  of  the  Riding  of  the 
Schools — The  back  of  a  Jockey  and  the  figure  of  a 
Cavalry  Officer. 

Chapter  V.  —  Exercises  which  do  not  Produce 
Deformity 327 

The  best  Gymnastic  Exercises — Ground  Exercises — An  Exercise 
too  Httle  regarded  ;  French  Boxing  or  Chausson— Y^ay 
division  of  work  in  this  Exercise;  Necessity  for  Perfect  Equili- 
brium ;  Boldness  of  the  Movements — The  Turning  Kick— 
Swimming  and  Climbing— Rowing — Two  Varieties  of  Boatmg 
Exercise;  the  Oar  and  the  Paddle — Superiority  of  the  Oar 
—Rowing  and  Sculling — General  conditions  of  Exercises 
which  do  not  produce  Deformity  ;  these  conditions  are 
especially  Negative  —  Natural  tendency  of  the  Body  to 
Regular  Development —  Exercise  must  not  oppose  this 
tendency — Suppleness  a  condition  of  Elegance  of  Figure 
—Superiority  of  Exercises  of  Skill  to  Exercises  of  Strength 
— Rope-Dancers  ;  Jugglers  and  Balancers— The  habit  of 
carrying  Burthens  on  the  Head — The  Women  of  Teneriffe. 


CONTENTS.  XV 

PART    VI. 
THE  OFFICE  OF  THE   BRAIN  IN  EXERCISE- 

OVERWORK  IN  SCHOOLS  —  MENTAL  AND  PHYSICAL 
EXERCISE  —  EXCITO-MOTOR  WORK  —  WORK  OF 
LATENT  STIMULATION — THE  WORK  OF  CO-ORDINA- 
TION  IN    EXERCISE — AUTOMATISM   IN    EXERCISE. 

Chapter  I. — Overwork  in  Schools  ....  339 
The  Scholastic  Regimen — Report  of  the  French  Academy  of 
Medicine — "  Mental  Os^erwork  and  Sedentary  Li/e''^ — Proposed 
Remedies;  a  more  Simple  course  of  Study  and  more  Physical 
Exercise — How  these  Reforms  must  be  applied  —  Their 
Mutual  Dependence — Difficulty  of  Simplifying  the  Course  of 
Study — Dangers  of  more  Physical  Exercise  without  Dimi- 
nution of  Mental  Work — Are  Bodily  Exercises  Recrea- 
tion for  the  Brain  —  Unrecognised  Importance  of  care  in 
the  Choice  of  an  Exercise  for  the  Needs  of  Cerebral  Hygiene. 

Chapter  II. — Mental  Work  and  Physical  Exercise  .  344 
The  Muscle  which  Works  and  the  Brain  which  Thinks — Simi- 
larity of  the  Physiological  Phenomena — Heating  of  the  Brain 
— Experiments  of  Dr.  Lombard — Flow  of  Blood  to  the  Brain 
during  Mental  Exertion — The  Balance  of  Mosso— The  conse- 
quences of  Work  of  the  Mental  and  of  the  Physical  Order 
— Combustions  and  Products  of  Dissimilation — Auto-intoxi- 
cation through  Overwork  —  Similarity  of  effects  in  the 
Physical  and  in  the  Psychical  Order — Effects  of  Brain  Work 
on  the  Composition  of  the  Urine  ;  they  are  Identical  with 
those  of  Muscular  W^ork  —  An  Attack  of  Gout  following 
Mental  Fatigue  like  one  following  Physical  Fatigue  —  The 
Case  of  Sydenham. 

Chapter  III. — Excito-motor  Work  .  .  •  ,352 
Necessary  association  of  the  Nerve- Cell  and  the  Muscular 
Fibre  in  Movements  —  Origin  of  Motor  Stimuli  —  Nerve 
Centres — The  Spmal  Cord  a  Centre  of  Unconscious  Move- 
ments, the  Brain  a  Centre  of  Voluntary  Movements — Office 
of  the  Grey  Matter  of  the  Brain — The  Dog  of  Professor  Goltz 
— A  counter- proof,  the  Observation  of  Dr.  Luys  —  Muscular 
Work  and  Nervous  Work  in  Voluntary  Movements — 
Frequent  Disproportion  between  the  Effort  of  Will  and  the 
Muscular  Exertion  —  Conditions  which  make  the  Relation 
vary  between  the  Expenditure  of  Nervous  Energy  and  the 
Mechanical  Work  of  the  Muscles — Diminution  of  Muscular 
Irritability — Muscular  Fatigue. 


XVI  CONTENTS. 

Chapter  IV. — Work  of  Latent  Stimulation  ,  .353 
A  Cat  lyin^-in-wait  for  a  Mouse — Lying-in-wait  in  Animals. 
Nervous  Work  which  this  Action  needs — Identity  of  Certain 
Phases  of  Bodily  Exercises  with  the  Phenomenon  of  lying- 
in-wait —  A  Fencing-Bout  —  Physiological  analysis  of  the 
"Direct  Blow" — Fencers  who  have  "Quickness" — Readiness 
of  Blow — Latent  Stimulation  of  Muscle  and  Diminution  of  the 
Latent  Period — Explanation  deduced  from  the  Discovery  of 
Helmholtz — The  Office  of  the  Brain  in  Fencing — How  the 
Fencer  betrays  his  Intentions — Advice  of  Bazancourt — Effects 
of  Work  of  Latent  Stimulation — Nervous  Fatigue  and  Intellec- 
tual Fatigue — Nervous  Fatigue  :  its  Effects  on  Nutrition — 
Why  Cats  do  not  become  Fat. 

Chapter  V. — The  Work  of  Co-ordination  in  Exercise  36g 
Difficult  Exercises— Skill  in  Exercises— Circling  the  Trapeze- 
Apprenticeship  of  Movements — Precision  in  Muscular  Actions 
— Office  of  the  Brain  and  of  the  Psychical  Faculties  in  the  Co- 
ordination of  Movements — A  Dancing  Lesson — Muscular 
Education — Economy  of  Muscular  Force  and  of  Nervous  Ex- 
penditure, with  equal  Mechanical  Work — Improvement  of  the 
Muscular  Sense  —  St.  Vitus's  Dance  —  Hygienic  Use  and 
Importance  of  Difficult  Exercises — Persons  who  should 
Refrain  from  them — Error  usually  Committed  in  the  Choice 
of  an  Exercise. 

Chapter  VI.— Automatism  in  Exercise  .  ,  .381 
Movements  Performed  without  the  Intervention  of  the  Brain — 
Decapitated  Animals — A  Curious  Spectacle  Invented  by  the 
Emperor  Commodus — Organs  which  Perform  their  Functions 
Automatically  —  Unconscious  Movements  —  Office  of  the 
Spinal  Cord — Conditions  of  Automatism  in  Exercise — Influ- 
ence of  Rhythm;  Movements  with  a  Cadence — Danci?tg 
Tunes — Influence  of  Apprenticeship — Necessity  for  Absence 
of  Effort  in  Automatic  Movements — Regularity  of  Automatic 
Actions — A  Personal  Observation  ;  Automatism  in  Rowing— r 
Persistence  of  Automatic  Actions — "Memory"  of  the  Spinal 
Cord — How  Different  Paces  are  Created — Tenacity  of  Early 
Muscular  Habits  —  Quickness  in  Fencing  —  Race-Horses 
Trained  too  Slowly — Effects  of  Automatism  in  Exercise — 
Economy  of  Voluntary  Nervous  Energy — The  Brain  supple- 
mented by  the  Spinal  Cord  —  Repose  of  the  Psychical 
Faculties — Superiority  of  Automatic  Exercises  in  Cases  of 
Cerebral  Fatigue. 


PART     1. 
MUSCULAR    WORK. 

THE     ORGANS      OF     WORK MOVEMENTS HEAT- 
COMBUSTION. 


CHAPTER  I. 

THE   ORGANS   OF    MOVEMENT. 

Exercise  and  Work— Muscle— Nerve  :  Avalanche  Theory.  The 
Spinal  Cord  ;  Reflex  Actions  ;  Unconscious  Movements— The 
Brain  ;  Reflex  Movements  ;  Voluntary  Movements— The 
]\Iotor  Centres  ;  associated  Muscular  Actions.  The  Will, 
Agent  of  Work.  Muscular  Contraction— Course  of  a  Volun- 
tary Stimulus  ;  IMode  of  Transmission— Nervous  Vibration 
and  the  Muscular  Wave — Time  of  Transmission;  Latent 
Period. 

By  bodily  exercise,  we  mean  work  done  with  the  object 
of  perfecting  the  human  organism  from  ths  point  of 
view  of  strength,  skill,  or  health. 

Scientifically  speaking,  there  is  no  difference  between 
the  professional  labour  which  circumstances  demand 
from  the  peasant  or  workman,  and  the  more  or  less 
refined  exercise  to  which  a  sportman  devotes  himself. 
The  manual  labourer  who  chops  wood,  and  the  gentle- 
man who  fences,  both  perform  muscular  work.  But  the 
gentleman  has  his  exercise  at  his  own  hours,  regulates 
to  his  own  taste  the  time  he  allots  to  it,  following  the  calls 
of  hygiene,  diet  and  rest,  while  the  poor  man  works  too 
much,  feeds  badly,  and  sleeps  little. 

This  is  why  work  wears  out  the  one,  while  exercise 
strengthens  the  other. 

But  what  the  workman  does  of  necessity,  the  man  en- 
amoured of  violent  exercises  can  do  by  excessive  ardour. 
In  the  two  cases  the  result  is  the  same,  and  the  abuse  of 
athletic  exercise  causes  exhaustion  and  overwork  as 
surely  as  does  excessive  labour. 

Bodily   exercise   and   labour   are   then    synonymous 


4  PHYSIOLOGY  OF  BODILY  EXERCISE. 

from  the  physiological  point  of  view,  and  we  shall  blend 
them  in  our  study  by  referring  them  to  their  funda- 
mental principle,  muscular  contraction, 

I. 

The  immediate  agents  in  movement  are  the  muscles^ 
bundles  of  reddish  fibres  which  collectively  form  the 
fleshy  masses  surrounding  the  different  parts  of  the 
skeleton. 

The  muscles  form,  by  weight,  more  than  half  of  the 
human  body.  Hence  the  importance  of  rnuscular 
exercise  in  modifying  nutrition.  Work  in  fact,  changes 
profoundly  the  physiological  condition  and  the  chemical 
composition  of  muscles,  and  many  exercises  cause  all 
the  muscular  regions  of  the  body  to  work  at  once.  We 
can  understand  that  the  whole  system  associates  in  the 
modifications  produced  in  so  important  a  member  of  the 
living  tissues. 

The  muscular  tissues  of  the  body  are  divided  into 
larger  or  smaller  bundles  of  fibres,  which  are  generally 
of  an  elongated  shape,  and  have  two  extremities,  each 
usually  ending  in  a  tendon  attached  to  a  bone.  Each  of 
these  masses  forms  a  muscle,  and  every  muscle  consists 
of  secondary  fasciculi.  Finally,  these  secondary  fasciculi 
may  be  split  up  into  primitive  fibres^  the  fundamental 
elements  of  the  organ. 

The  primitive  muscle-fibres  are  essentially  made  up 
of  a  kind  of  membranous  sheath  called  the  sarco- 
lemma^  enclosing  the  muscular  juice. 

The  muscular  juice  or  plasma  is  quite  fluid  at  a  low 
temperature.  Kiihn  gives  us  a  curious  proof  of  this  : 
he  saw  a  parasitic  worm  swimming  in  a  lively  manner 
in  the  interior  of  a  primitive  fibre.  But  we  can  only 
prove  the  fluidity  of  the  plasma  by  the  considerable 
degree  of  cold  which  congeals  the  other  constituents  of 
muscle.  To  see  it  in  a  liquid  state  it  must  be  observed 
above  3°  C.  When  cooled,  it  already  tends  to  coagulate 
at  0°  C,  and  when  heated  up  to  45°  C.  it  suddenly  be- 
comes solid. 

The  plasma  does  not  only  coagulate  under  the  in- 


THE   ORGANS   OF    MOVEMENT.  5 

fluence  of  heat  It  also  tends  to  solidify  when  treated 
with  certain  acids,  notably  lactic  acid,  which  is  formed 
in  muscles  in  action. 

We  shall  see,  in  discussing  the  phenomena  of  fatigue, 
how  important  a  part  in  acute  overwork  is  played  by 
the  coagulation  of  the  muscle-plasma  under  the  in- 
fluence of  excessive  heat  and  of  the  numerous  acid  pro- 
ducts which  develop  in  the  over-driven  muscle. 

Muscles  possess  the  property  of  contraction,  that  is  to 
say,  of  shortening,  and  bringing  their  extremities  nearer 
to  each  other,  after  the  manner  in  which  a  stretched 
caoutchouc  cord  returns -to  its  former  size. 

When  a  muscle  contracts  it  exercises  a  tension  on  the 
bones  to  which  it  is  attached.  Thanks  to  the  varied 
effects  of  levers,  pulleys,  pivots,  etc.,  of  which  the  joints 
are  made  up,  the  fundamental  movement  of  traction  is 
very  variously  transformed,  and  the  limbs  are  flexed, 
extended,  turned  and  returned  in  all  directions. 

The  muscles  are  charged  with  the  performance  of 
movements,  but  they  cannot  bring  them  about  indepen- 
dently, without  the  assistance  of  an  agent  which  throws 
them  into  contraction.  The  contractile  force  of  muscles 
is  a  latent  energy  comparable  to  that  of  gunpowder, 
which  cannot  explode  without  a  spark.  A  muscle  left 
to  itself  remains  inert,  and  cannot  arise  from  its  inaction, 
from  its  repose,  unless  made  to  do  so  by  some  stimulus. 

The  stimulus  most  commonly  employed  is  the  will, 
but  many  other  agents  can  bring  into  play  the  con- 
tractile properties  of  muscle.  Any  mechanical, 
physical,  or  chemical  action  on  a  muscle,  a  blow,  a 
pinch,  an  electric  discharge,  the  contact  of  a  strong  acid, 
etc.,  can  play  the  part  of  a  stimulus,  and  cause  contrac- 
tions and  movements. 

In  order  to  bring  into  play  the  irritability  of  a  muscle, 
the  property  which  causes  the  organ  to  contract  when 
stimulated,  it  is  sufficient  to  apply  the  stimulus  directly 
to  the  muscular  fibre.  Thus,  in  an  animal  just  killed, 
it  is  enough  to  expose  a  muscle  and  pinch  its  fibres 
strongly,  and  the  muscle  is  seen  to  contract,  and  to  move 
the  bones  to  which  it  is  attached. 


6  PHYSIOLOGY  OF  BODILY  EXERCISE. 

At  first  sight  we  are  disposed  to  think  that  the  will, 
like  other  muscle-stimuH,  acts  directly  on  the  motor 
organ. 

Willing  and  doing  seem  so  intimately  connected  with 
each  other,  that  they  appear  to  fuse.  At  the  slightest 
command  our  hand  seizes  an  object,  places  or  dis- 
places it,  and  obeys  with  such  punctuality  and  quick- 
ness, that  the  will  seems  to  stimulate  the  muscles 
directly.  But  it  is  not  so,  and  the  faculty  of  will  needs, 
for  the  transmission  of  its  orders,  a  very  complicated 
mechanism  of  intermediate  organs,  without  which  its 
action  is  ineffectual. 

These  intermediate  organs  are  the  nerves,  the  spinal 
cord,  and  the  brain. 

If  the  nerves  of  the  arm  are  cut,  the  most  energetic 
will  in  vain  exhausts  itself  in  the  endeavour  to  move  the 
limb  ;  the  muscles  contract  no  longer. 

It  is  generally  stated  that  the  section  of  motor  nerves 
paralyses  muscles.  The  expression  is  inaccurate  ;  these 
muscles  have  not  lost  the  power  of  contraction,  but  they 
are  removed  from  the  influence  of  the  will,  and  receive 
its  orders  no  longer.  Acted  on  by  other  stimuli,  they 
would  still  contract  and  move  the  bones  to  which  they 
are  attached.  If  we  galvanise  these  muscles  which 
seem  paralysed,  if  indeed  we  simply  pinch  th:m  strongly, 
we  produce  contractions  and  movements. 

Section  of  the  spinal  cord,  lesion  of  the  brain,  have 
the  similar  result  of  putting  the  muscles  out  of  reach  of 
the  will,  without,  for  all  that,  destroying  their  con- 
tractility. 

Contractility  is  a  force  inherent  in  muscle,  and  is  not 
supplied  to  it  by  its  motor  nerve.  If  we  carefully 
destroy  all  the  nervous  filaments  going  to  a  muscle,  the 
latter,  reduced  to  its  own  elements,  nevertheless  retains 
the  power  of  contracting  under  the  influence  of  a 
stimulus. 

A  muscle  has  an  individuality  and  a  power  peculiar  to 
itself,  independent  of  any  nervous  action. 

If  a  muscle  be  detached  from  the  leg  of  a  recently 
killed  dog,  this  muscle,  thus  isolated,  being  no  more  than 


THE   ORGANS   OF   MOVEMENT.  7 

a  fragment  of  the  body  of  the  animal,  may  be  made  to 
do  work.  If  we  attach  the  muscle  by  a  nail  at  one  end, 
and  fasten  to  the  other  end  a  hanging  weight,  it  is 
enough,  the  muscle  being  in  this  manner  stretched, 
strongly  to  pinch  the  fibres  to  cause  the  muscle  to 
contract  and  to  raise  the  weight 

Muscle  has  great  vital  energy,  and  long  retains  the 
power  of  action,  provided  that  it  receives  a  sufficient 
stimulus.  Thus  in  many  cases  the  loss  of  power  of 
action  shown  by  a  fatigued  man  must  not  be  attributed 
to  the  muscular  system.  Almost  always,  in  the  ordinary 
course  of  life,  it  is  the  will — the  stimulus  of  muscular 
contraction — which  first  gives  out,  long  before  the  muscle 
has  lost  its  contractile  powers,  under  the  influence  of 
prolonged  work. 

II. 

We  may  compare  motor  nerves  to  the  wires  which 
conduct  electricity  from  an  electro-motor  to  a  receiving 
apparatus.  They  convey  to  the  muscles  the  stimuli 
emanating  from  the  brain.  They  convey  also  all  stimuli 
which  can  come  from  outside  agents.  A  pinch,  an 
electric  shock,  the  contact  of  an  acid,  can  throw  the 
muscle  into  action  by  the  mediation  of  the  nerve.  If  a 
nerve  be  electrified  the  effect  produced  on  the  muscle  to 
which  this  nerve  is  distributed  will  be  identical  with 
that  which  would  be  produced  by  electrifying  the  muscle 
directly. 

The  will  needs  the  help  of  the  nerves  to  transmit  to 
the  muscles  the  orders  to  act.  In  the  most  vigorous  and 
energetic  man,  it  suffices  to  cut  one  of  these  slender 
little  filaments,  to  see  the  muscles  supplied  by  it  become 
inert.  The  will  then  exhausts  itself  in  useless  efforts, 
and  gives  in  vain  repeated  orders.     Its  call  is  unheard. 

Similarly  the  breaking  of  the  wires  between  two  tele- 
graphic stations,  renders  all  communication  impossible. 

The  nerves  have  not  in  themselves  any  power  of 
producing  movements  Their  function  is  merely  to 
transmit  to  the  muscles  the  stimuli  which  bring  theiï 
vital  properties  into  play. 


8  PHYSIOLOGY  OF   BODILY  EXERCISE. 

We  must  mention,  however,  that  according  to  certain 
physiologists,  a  nerve  has,  besides  the  power  of  conduct- 
ing a  stimulus  received  by  it,  the  further  power  of  rein- 
forcing that  stimulus. 

According  to  Pfliiger,  when  a  nerve  is  stimulated, 
whether  by  a  mechanical  shock,  an  electrical  discharge, 
or  by  the  action  of  the  will,  a  phenomenon  occurs  which 
this  physiologist  calls  the  nervotis  avalanche.  Just  as  a 
lump  of  snow  detached  from  a  mountain  top  grows  as 
it  descends  the  snowy  slope,  and  when  it  reaches  the 
valley  is  of  larger  size  than  when  it  set  out,  so  the 
stimulus  received  by  the  nerve  is  amplified  in  its  passage 
through  the  conducting  filament,  and  is  much  more 
intense  when  it  reaches  the  muscle  than  it  was  when 
first  produced. 

The  nerve  would  then  be  a  reinforcing  as  well  as  a 
conducting  apparatus  :  it  would  increase  the  intensity  of 
the  stimuli  which  it  transmits,  as  the  microphone  in- 
creases the  intensity  of  the  sounds  which  pass  through  it. 

If  Pfliiger's  theory  is  correct,  and  if  the  nerve  really 
has  the  power  of  amplifying  the  stimuli  which  it  conveys 
to  the  muscle,  we  may  believe  that  this  power  is  de- 
veloped by  exercise,  like  all  the  physiological  functions 
of  working  organs.  The  motor  nerves  of  a  man  who 
devotes  himself  to  bodily  exercise  should  then  become 
more  capable  of  reinforcing  the  voluntary  stimuli. 

This  property  could  be  a  partial  cause  of  the  some- 
times surprising  increase  of  power  displayed  by  trained 
men,  which  cannot  always  be  explained  by  an  increase 
of  the  muscular  tissues  ;  it  would  render  it  possible  to 
produce,  with  a  moderate  effort  of  will,  a  more  intense 
stiumlation  of  the  motor  fibre,  and  consequently  a  more 
energetic  contraction. 

Of  all  nervous  tissues  the  nerves  have  the  simplest 
structure,  for  they  have  only  one  fundamental  tissue, 
the  white  matter.  This  is  made  up  of  elongated  ele- 
ments in  the  form  of  hollow  fibres,  or  tiibes  in  which  is 
seen,  with  the  microscope,  a  kind  of  filament  called  the 
axis-cylinder.  At  the  point  where  the  motor  nerve  is 
distributed  to  a  muscle,  the  axis-cylinder  ends  in  a  disc- 


THE  ORGANS  OF   MOVEMENT.  9 

shaped  expansion  called  the  motor  end-plate,  which  is 
intimately  connected  with  the  enveloping  sheath  of  the 
ultimate  muscle  fibres.  The  motor  end-plate  is  the 
junction  which  unites  nerve  and  muscle.  By  its  means 
a  communication  is  established  between  the  motor  organ 
and  the  conductor  which  conveys  to  it  the  orders  of  the 
will. 

III. 

The  spinal  cord  seems  to  be  formed  by  the  union  of 
all  the  nerves  of  the  trunk  and  limbs.  It  has  the  shape 
of  a  thick  white  cord,  in  connection  with  which  are  both 
the  motor  and  the  sensory  nerves,  and  which  is  con- 
tinuous with  the  brain,  of  which  it  is  in  a  certain  sense  a 
prolongation. 

It  is  made  up  of  two  kinds  of  tissue  :  one  is  white  like 
the  tissue  of  the  nerves,  and  the  other  h  is  a  grey  colour. 

The  white  matter  forms  the  exteinil  layers  of  the 
cord.  It  has  the  same  elementary  structure  as  the 
nerves  and  possesses  the  same  conducting  properties  as 
these  organs  ;  but  being  formed  of  sensory  as  well  as  of 
motor  fibres,  it  has  mixed  functions  :  the  posterior 
region  conducts  sensory  impressions,  whilst  the  anterior 
region  transmits  motor  stimuli. 

As  far  as  the  white  matter  is  concerned,  the  spinal 
cord  does  not  dift'er  at  all  from  the  nerves.  If  we  make 
a  transverse  section,  the  voluntary  movements  of  all 
muscles  which  receive  their  nerves  from  the  cord  below 
the  section  are  abolished.  If,  however,  we  pinch 
strongly,  or  electrify  the  anterior  tracts,  we  produce  in- 
voluntary contractions  in  the  muscles  innervated  by 
the  points  to  which  the  stimulus  is  applied. 

The  grey  matter  makes  the  spinal  cord  a  nerve-centre^ 
that  is  to  say,  an  organ  capable  not  only  of  conducting 
a  motor  stimulus,  but  also  of  spontaneously  bringing 
about  a  movement  in  the  muscular  system.  It  is  made 
up  of  irregularly  spherical  cells  which  have  filamentous 
processes  putting,  them  in  communication  one  with  the 
other,  and  anatomically  and  physiologically  with  the 
motor  and   sensory  nerve  fibres.     The  nerve-cell  is   the 


lO  PHYSIOLOGY  OF   BODILY  EXERCISE, 

most  exalted  element  in  the  hierarchy  of  living  tissues  : 
when  we  find  one  in  any  part  of  the  nervous  system,  we 
may  be  certain  that  this  region  possesses  a  power  proper 
to  itself  and  independent  of  any  other  part. 

The  special  power  of  the  spinal  cord  is  shown  by  the 
faculty  which  it  has  of  calling  forth  motor  stimuli  in 
the  muscles  without  the  help  of  the  brain  and  without 
the  order  of  the  will. 

Decapitated  animals  can  make  spontaneous  move- 
ments, provided  that  their  spinal  cord  is  untouched. 

A  duck  whose  head  has  just  been  cut  off  flaps  its 
wings  and  can  even  walk  a  few  steps. 

On  the  body  of  a  man  just  decapitated,  if  we  strongly 
pinch  the  arm  or  the  leg,  the  limb  is  drawn  away  as  if 
the  executed  man  felt  the  impression  received  by  the 
skin,  and  tried  to  escape  from  it. 

All  these  movements  have  the  appearance  of  voluntary 
movements  ;  they  are  however  unconscious  and  in- 
voluntary, like  all  those  executed  without  the  concur- 
rence of  the  brain.  To  give  an  idea  of  the  power  of 
the  spinal  cord  when  reduced  to  its  own  resources  and 
acting  without  the  aid  of  the  brain,  we  cannot  do  better 
than  quote  the  following  curious  experiment  : — 

"If  we  cut  off  the  head  of  a  frog,  the  animal  jumps 
and  twists  for  an  instant,  and  then  is  still.  It  would  for 
ever  remain  motionless  if  kept  under  a  bell-glass,  in  a 
damp  atmosphere,  and  sheltered  from  all  stimulation. 
But  if  we  touch  one  of  its  legs,  or  drop  on  it  a  little 
vinegar,  the  frog  immediately  tries  to  escape  and  to  put 
at  a  distance  the  cause  of  disturbance.  If  the  drop  of 
vinegar  is  on  the  right  leg,  it  endeavours  to  wipe  it  off 
with  the  left,  and  vice  versa'' 

At  first  sight  this  appears  intelligent,  and  the  frog 
seems  to  have  made  a  conscious  voluntary  act  ;  if  how- 
ever we  continue  the  experiment  we  see  that  the 
movement  of  the  decapitated  frog  is  nothing  but  a 
mechanical  response  to  a  lively  stimulus,  and  in  no  sense 
an  action  calculated  with  a  view  of  escaping  danger. 

"  Goltz  and  Portes,  having  taken  a  frog,  removed  the 
brain   and   then  plunged   the   animal    into   water   in  a 


THE  ORGANS   OF   MOVEMENT.  II 

glass  vessel.  When  touched,  it  swam  as  if  to  escape, 
and  even  jumped  out  of  the  vessel.  But  on  warming 
the  water  very  slcwly,  in  such  a  manner  as  to  reach  a 
very  high  temperature  without  any  abrupt  transition, 
the  frog  did  not  move,  nor  try  to  jump  out  of  the  vase, 
but  in  the  end  was  boiled  without  having  made  any 
action  indicating  a  consciousness  of  danger."  * 

The  movements  of  a  decapitated  frog  are  reflex  move- 
ments. In  reflex  movements  the  will  has  no  place. 
That  which  excites  the  muscular  action  is  a  sensation 
which  runs  up  the  whole  length  of  a  sensory  nerve  to  a 
given  point  of  the  spinal  cord,  from  which  a  motor  nerve 
starts.  The  end  of  the  sensory  nerve  and  the  beginning 
of  the  motor  nerve  join  in  the  same  cell  of  the  cord,  from 
which  is  given  off  a  third  nervous  filament  in  the  direc- 
tion of  the  brain. 

When  the  sensory  impression,  in  place  of  travelling 
towards  the  head  by  this  third  ascending  filament,  stops 
in  the  spinal  cord,  the  latter  sends  it  on  transformed  into 
movement  in  the  direction  of  the  muscle,  whither  it  is 
conducted  by  the  motor  nerve.  The  impression  is 
reflected  at  the  motor  centre  and  returns  upon  its  steps 
instead  of  continuing  its  journey,  just  as  are  reflected 
the  sonorous  waves  of  the  voice,  which,  striking  against 
a  wall,  rebound  to  produce  an  echo. 

We  may  say  that  a  reflex  movement  is  the  echo  of  a 
sensory  impression. 

It  is  not  necessary  that  the  brain  should  be  destroyed 
for  the  production  of  reflex  movements  :  it  is  enough 
that  it  takes  no  part  in  the  muscular  action.  This 
being  the  case,  the  latter  is  not  willed  and  is  produced 
unconsciously,  as  may  be  observed  in  a  sleeping  man, 
or  even  one  preoccupied,  who,  according  to  a  common 
expression,  "  has  his  head  in  the  clouds,"  and  does 
not  think  about  what  he  is  doing.  We  may  con- 
stantly see  a  preoccupied  man  walk  past  his  own 
doorway  which  he  intended  to  enter.  We  say  that  he 
is  distracted,  and  that  his  legs  work  with  an  automatic 

*  Mosso.     La  Peur. 


12  PHYSIOLOGY  OF  BODILY  EXERCISE. 

movement.  This  autc  Tiatic  movement  of  walking  was 
at  first  very  laboriously  acquired  by  the  infant,  later  it 
has  become  so  easy  of  execution  that  the  brain  takes 
no  part  in  it.  The  sensation  which  the  ground  produces 
on  the  sole  of  the  foot  resting  on  it  determines,  as  a 
reflex  effect,  a  movement  of  the  other  leg  which  comes 
in  its  turn  to  a  position  in  front  of  the  first,  and  so  on. 
This  regular  succession  of  movements  of  the  legs,  which 
now  rest  on  the  ground,  now  are  raised  from  it,  can 
take  place  without  the  will  playing  any  part  in  it,  or  the 
brain  being  conscious  of  it 

In  bodily  exercise  a  number  of  movements  become 
automatic  by  habit,  and  it  comes  to  pass  that,  during 
their  performance,  the  will  can  be  occupied  about  other 
things,  without  participating  in  the  action  of  the 
muscles  In  this  case  the  spinal  cord  alone  presides 
over  these  movements  without  any  intervention  of  the 
brain. 

We  shall  have  an  opportunity,  in  discussing  the  thera- 
peutical applications  of  exercise,  of  profiting  by  the 
summary  of  ideas  we  have  just  expounded.  We  shall 
show  how  important  it  is  that  a  man  suffering  from 
mental  overwork  should  seek  by  preference  automatic 
exercises,  which  do  not  bring  the  action  of  the  brain 
into  play. 

In  many  cases  the  spinal  cord  is  able,  thanks  to  its 
auto-motor  power,  to  take  the  place  of  the  brain,  and 
preside  alone  over  very  complicated  movements.  But 
its  absolute  integrity  is  necessary  for  the  performance 
of  automatic  or  reflex  actions.  If  a  probe  be  thrust 
down  the  spinal  canal  of  a  recently  decapitated  frog,  its 
reflex  power  is  completely  annihilated,  consequent  on 
the  destruction  of  the  cord,  which  is  broken  up  by  the 
instrument.  At  the  same  moment  the  animal  loses  all 
power  of  reaction  to  an  agent  which  calls  forth  the 
sensibility  of  the  skin  :  no  movements  can  be  produced 
in  the  limbs  except  by  directly  exciting  the  muscles  ot 
their  motor  nerves. 


THE  ORGANS   OF   MOVEMENT.  1 3 


IV. 

The  Brain  is  a  rounded,  soft,  greyish  mass.  It  is 
composed,  like  the  spinal  cord,  of  grey  and  white  matter, 
and  like  the  cord,  consists  of  nerve  fibres  and  cells. 
But — just  the  opposite  of  what  we  observed  in  the 
cord — the  grey  matter  occupies  the  periphery,  the  cortex 
of  the  brain,  while  the  white  matter  is  in  the  centre  : 
further,  in  the  thickness  of  the  white  matter  are  im- 
portant nuclei  of  grey  matter,  indicating  the  presence, 
in  certain  central  regions  of  the  organ,  of  nerve  cells, 
foci  of  independent  activity. 

In  the  brain,  as  in  the  cord,  the  white  matter  conducts 
the  stimuli  it  receives,  while  the  power  of  sending  forth 
spontaneous  motor  stimuli  devolves  on  certain  cells  of 
the  grey  matter. 

The  grey  matter  of  the  brain  can,  like  that  of  the 
cord,  manifest  its  proper  activity  by  reflex  effects. 
The  brain  gives  origin  to  motor  and  sensory  nerves,  and 
a  sensory  impression  can  give  rise  to  a  reflex  movement 
in  muscles  supplied  by  cranial  nerves.  It  is  in  this 
manner  that,  in  a  recently  decapitated  animal,  a  drop  of 
vinegar  applied  to  the  surface  of  the  eye  produces  a 
closure  of  the  eyelids. 

The  brain  is  then,  like  the  spinal  cord,  a  centre  of 
reflex  motion  ;  but  it  is  further  a  centre  of  voluntary 
motion. 

This  is,  from  the  point  of  view  of  movements,  the 
characteristic  of  the  brain  :  when  the  brain  is  removed, 
every  willed  muscular  action  disappears  with  it. 

It  is  not  necessary  to  remove  the  whole  of  the  brain 
in  order  to  deprive  an  animal  of  the  power  of  mani- 
festing its  will  by  conscious  actions.  It  is  sufficient  for 
this  purpose  completely  to  destroy  the  grey  matter,  for 
it  is  in  the  interior  of  this  tissue  that  the  voluntary 
stimuli,  the  nature  of  which  is,  up  to  the  present  time, 
unknown,  are  elaborated.  It  is  practicable  to  keep  dogs 
deprived  of  this  part  of  the  brain  alive,  and  we  may  be 
3 


14  PHYSIOLOGY  OF  BODILY  EXERCISE. 

certain  that  all  their  movements  are  reflex  actions 
aroused  by  the  medium  in  which  they  live,  and  directed 
by  habit.     They  only  move  now  automatically. 

Like  the  spinal  cord  and  the  motor  nerves,  the  brain 
possesses  the  power  of  transmitting  mechanical  or  elec- 
trical stimuli  applied  to  it.  But  it  is  easy  to  foretell 
what  effects  the  stimulation  of  a  nerve  will  produce  on 
the  organs  of  movement,  for  we  know  exactly  to  what 
muscles  this  nerve  is  distributed,  while  it  is  difficult  to 
specify  the  effect  of  a  motor  stimulus  applied  to  the 
brain.  In  fact  we  do  not  always  know  which  groups  of 
muscles  correspond  to  the  nerve-fibres  which  -we  stimu- 
late. Hence  the  often  unexpected,  and  sometimes  very 
remarkable  results  of  wounds  of  the  brain. 

While  out  shooting,  we  sometimes  see  wounded 
animals  make  singular  movements. 

A  partridge,  for  instance,  wounded  in  a  particular 
part  of  the  head,  rises  all  at  once  vertically  to  a  great 
height  in  the  air,  and  falls  back  dead. 

We  once  observed  a  wounded  hare  turning  round  and 
round  with  great  rapidity.  The  movement  was  made 
round  the  longitudinal  axis  of  the  body  ;  that  is  to  say, 
the  animal  seemed  to  revolve  round  a  rigid  rod,  tra- 
versing it  from  head  to  tail.  We  thought  at  first  that 
the  wounded  hare  was  endeavouring  to  run  away,  and 
we  were  surprised  at  the  awkwardness  of  its  attempts  to 
escape.  But  we  were  soon  convinced  that  these  sin- 
gular revolutions  were  quite  involuntary  ;  they  were 
produced  by  an  irresistible  impulse.  The  hare  had 
received  a  shot  in  the  head,  and  this  shot,  perforating 
the  skull,  had  injured  one  of  the  crura  of  the  cerebellum. 
The  shock  received  by  the  motor  nerve-fibres  had 
stimulated  all  the  muscles  with  which  they  were  con- 
nected, and  these  muscles,  contracting  all  together,  had 
produced  in  the  animal  a ^râ:/^;j  movement  with  which 
the  will  had  nothing  to  do. 

Other  wounds  of  the  brain  can  produce  various  motor 
phenomena  which  are  no  less  surprising,  Thus,  by 
puncturing  certain  definite  points  of  the  encephalon,  we 
produce  what  are  known  as  circus  movements,  in  which 


THE  ORGANS  OF   MOVEMENT.  15 

the  wounded  animal  does  not  turn  on  its  own  axis,  but 
goes  round  and  round  like  a  horse  in  a  circus. 

The  physiological  explanation  of  these  movements  is 
still  unsatisfactory,  but  they  undoubtedly  show  that  a 
stimulus  applied  to  a  single  very  localised  part  of  the 
brain  can  produce  contractions  of  several  groups  of 
muscles  at  once. 

We  see  then,  that  owing  to  a  peculiar  anatomical 
arrangement,  a  great  number  of  motor  nerve-fibres, 
radiating  towards  different  muscles,  can  start  from  the 
same  very  limited  area  of  cerebral  substance.  In  this 
manner  a  stimulus,  which  acts  on  a  very  small  surface 
of  the  organ,  can  be  simultaneously  transmitted  to 
several  groups  of  muscles,  just  as  by  means  of  the 
multiple  communication  established  by  a  network  of 
wires,  a  single  button  can  throw  into  action  the  bells  of 
several  electric  apparatus. 

In  1874,  Ferrier  showed  that  by  applying  an  electric 
stimulus  to  certain  cerebral  convolutions,  movements 
were  produced  in  the  e}'e5,  the  tongue,  or  the  neck  of 
the  animal  under  experiment.  He  has  called  these 
regions  of  the  brain  to  which  appear  to  converge  a 
number  of  motor  nerve-fibres,  corresponding  to  well- 
determined,  and  sometimes  verv  extensive  muscular 
groups,  motor  centres. 

Bartholow,  an  American  doctor,  with  a  disregard  for 
the  human  subject  to  which  we  have  not  yet  attained  in 
Europe,  has  reproduced  on  a  man  whose  brain  was 
exposed  by  a  gun-shot  wound,  the  experiments  which 
Ferrier  made  on  dogs.  He  has  been  able  to  prove  that 
in  man,  as  in  other  animals,  there  are  motor  centres, 
circumsc^-ibed  areas  of  the  brain,  which  have  under  their 
control  the  movements  of  particular  regions  of  the  body. 

The  localisation  of  the  motor  power  for  a  whole 
group  of  muscles  in  a  limited  region  of  the  brain,  ex- 
plains the  common  action  of  certain  muscles,  and  the 
difficulty  experienced  in  making  one  muscle  act  u^ithout 
another.  The  will,  for  instance,  is  unabie  to  produce  an 
isolated  contraction  in  a  single  flexor,  or  a  single  ex- 
tensor muscle      When  the  will  commands,  it  is  obeved 


l6  PHYSIOLOGY  OF   BODILY   EXERCISE. 

by  a  whole  associated  group.  At  times,  however,  asso- 
ciated movements  are  less  intimately  connected,  and  it 
is  possible,  by  a  great  effort  of  the  will  and  by  continual 
practice,  to  learn  to  dissociate  two  movements  which  are 
ordinarily  in  combination. 

V. 

We  have  now  considered  the  organs  of  movement. 
The  nerves,  the  spinal  cord,  and  the  brain  are  so  many 
instruments  of  transmission  interposed  between  the  will 
and  the  muscles. 

The  brain,  with  its  motor  centres,  may  be  compared 
to  a  kind  of  keyboard,  each  key  of  which  corresponds  to 
a  certain  group  of  muscles,  and  on  which  the  will  strikes 
with  more  or  less  force,  according  as  it  wishes  to  pro- 
duce a  more  or  less  energetic  muscular  effort. 

How  is  the  communication  established  between  the 
will,  a  force  of  the  psychical  order,  and  a  material  sub- 
stance like  the  grey  matter  of  the  cerebral  convo- 
lutions ? 

This  is  a  problem  which  is  concerned  in  that  of  the 
relation  between  physical  and  moral  phenomena,  and 
which  has  not  yet  been  solved.  But,  whatever  may  be 
its  mode  of  action,  the  will  is  one  of  the  most  important 
factors  in  the  performance  of  movements,  one  of  the 
most  active  of  the  forces  concerned  in  muscular  work. 

Muscle  possesses  a  motor  force,  but  an  outside  agent 
must  intervene  that  this  force  may  come  into  action. 

Similarly,  a  bow  contains  a  specific  energy,  capable  of 
discharging  an  arrow,  but  an  archer  is  needed  to  bring 
into  play  the  elastic  force  of  the  wood.  The  will  is  just 
as  necessary  to  bring  the  muscles  into  action  as  the  arm 
of  the  archer  to  bend  the  bow  and  dispatch  the  shaft. 

The  will  is  the  exciting  cause  of  the  movement,  and 
the  movement  is  always  produced  with  a  vigour  propor- 
tional to  that  of  the  exciting  cause.  A  muscle  will 
remain  inert  if  we  endeavour  to  make  it  contract  by 
means  of  too  feeble  an  electric  current  ;  it  will  similarly 
be  incapable  of  action  if  stimulated  by  a  will  without 
energy.     Do  we  not  see  vigorous  men  lose  all  at  once 


THE   ORGANS   OF   MOVEMENT.  17 

their  muscular  power  when  their  will  is  paralysed  by  a 
depressing  emotion,  such  as  fear  ?  An  exciting  passion, 
Hke  anger,  on  the  other  hand,  increases  muscular  power, 
because  it  stimulates  the  will. 

Thus  is  explained  the  great  difference  between  the 
capabilities  for  work  of  two  equally  muscular  persons. 
One,  better  gifted  in  the  matter  of  will,  can  produce 
from  his  muscles  a  force  which  the  other  leaves  in  them, 
as  it  were,  latent. 

The  will  has  no  direct  action  on  muscles  any  more 
than  it  has  on  the  spinal  cord  or  on  the  motor  nerves. 
It  can  only  act  directly  on  the  grey  matter  of  the  cere- 
bral convolutions.  It  is  powerless  to  bring  the  muscular 
fibres  into  action  without  the  help  of  the  brain,  the  only 
organ  with  which  it  is  in  immediate  relation. 

The  brain  is  then  as  indispensable  an  organ  for  the 
performance  of  voluntary  movements  as  for  the  accom- 
plishment of  mental  work,  and  we  must  not  attribute 
exclusively  to  intellectual  occupations  the  privilege  ot 
making  this  organ  work.  Bodily  exercises  bring  it  into 
action  every  time  they  call  for  the  intervention  of  the 
will. 

By  what  mechanism  is  an  order  of  the  will  trans- 
mitted to  the  muscles  through  the  conducting  fibres  of 
the  brain,  the  spinal  cord,  and  the  motor  nerves  ? 

It  is  now  admitted  that  volition^  or  the  act  of  will, 
produces  a  molecular  disturbance  in  the  cells  of  the 
grey  matter,  and  that  this  disturbance,  passing  along 
the  nerve  fibres,  is  communicated  by  their  means  to  the 
muscular  fibres.  This  molecular  movement  has  been 
com. pared  to  the  wave  produced  on  the  surface  of 
smooth  water,  which  gradually  invades  the  liquid  sheet, 
as  soon  as  one  single  point  of  the  whole  mass  has  been 
disturbed  by  a  blow. 

The  production  of  an  undulatory  movement  has  not 
been  actually  demonstrated  in  the  cerebral  substancCj 
the  spinal  cord,  or  the  nerves  :  it  is  simply  a  very 
probable  hypothesis. 

On  the  other  hand  it  has  been  very  plainly  seen  in 


l8  PHYSIOLOGY  OF   BODILY   EXERCISE. 

muscle.  "  It  has  been  observed  in  living  muscle,  that 
at  stimulated  points  swellings  or  nodes  are  formed, 
which  then  run  along  the  whole  length  of  the  muscle 
like  a  wave  on  the  surface  of  water."  * 

By  means  of  ingeniously  constructed  registering  ap- 
paratus, Marey  has  been  able  to  take  a  graphic  tracing 
of  the  muscular  ivave.  Aéby  had  already  shown  in 
1862  that  in  living  animals  the  swelling  produced  at 
the  point  stimulated,  travelled  to  the  ends  of  the  muscle 
with  a  velocity  of  about  one  metre  per  second. 

Every  stimulus  received  by  a  muscle  gives  a  shock 
to  this  organ  which  is  transmitted  by  a  muscular  wave. 
If  the  stimuli  follow  each  other  quickly,  it  may  happen 
that  the  first  wave  is  still  going  on  when  the  second 
begins.  Then  we  see  the  two  swellings  run  one  after 
the  other  over  the  surface  of  the  stimulated  muscle.  If 
the  stimuli  are  repeated  very  quickly,  the  muscular 
waves  are  no  longer  seen,  and  one  swelling  occupies  the 
whole  muscle.  This  is  then  thickened  and  shortened 
uniformly  :  it  is  in  a  state  of  contraction. 

Between  the  moment  when  the  will  orders  a  contrac- 
tion, and  the  mçment  when  the  muscle  contracts,  there 
always  elapses  an  appreciable  interval  of  time.  This 
time  is  occupied  by  various  physiological  actions,  and 
in  the  first  place  by  the  transmission  of  the  nervous 
vibration.  The  disturbance  of  the  cerebral  cells  does 
not  instantaneously  reach  the  muscle.  It  has  first  to 
traverse  the  fibres  of  the  white  matter  of  the  brain, 
then  the  spinal  cord,  and  then  the  whole  length  of  the 
nervous  filament  which  passes  to  the  muscular  fibre. 
The  length  of  this  course  may  be  estimated  in  centi- 
metres, and  we  know  from  the  experiments  of  Helmholtz 
that  the  nervous  vibration  is  propagated  with  a  velocity 
of  about  35  metres  per  second.  It  is  then  easy  to 
calculate  from  these  data,  how  many  hundredths  of  a 
second  must,  for  example,  elapse,  from  the  moment 
when  a  man  wills  to  flex  his  foot,  and  the  moment  when 
the  foot  begins  to  move. 

*Marcy^  La  Machine  animale. 


THE  ORGANS  OF  MOVEMENT.  I9 

But  if  we  make  this  calculation  exactly  and  then 
compare  the  results  with  those  given  by  direct  observa- 
tion, we  discover  that  the  contraction  of  the  muscle 
is  retarded.  An  appreciable  interval  separates  the 
instant  at  which  the  stimulus  of  the  will  reaches  the 
muscle,  and  the  instant  at  v/hich  the  latter  responds  by 
a  contraction. 

This  period,  during  which  the  already  stimulated 
muscle  has  not  yet  begun  to  contract,  is  known  as  the 
period  of  latent  contraction. 

The  period  of  latent  contraction  is  not  always  of  the 
same  duration.  Many  circumstances  may  cause  a  varia- 
tion, but  increased  intensity  of  the  stimulus  received 
by  the  muscle  is  the  condition  which  most  efficiently 
shortens  the  latent  period.  To  a  feeble  stimulus,  the 
muscle  responds  slowly,  lazily  ;  an  energetic  shock  on 
the  other  hand  is  followed  by  a  prompt  contraction. 

It  was  established  by  Helmholtz  as  a  physiological 
law,  that,  the  length  of  the  latent  period  is  in  inverse  pro- 
portion to  the  intensity  of  the  stimulus  received  by  the 
muscle. 

When  the  will  orders  a  muscle  to  contract,  the  latter 
obeys  the  more  promptly,  the  more  violent  the  nervous 
disturbance  which  transmits  the  order. 

We  shall  see  later  what  we  shall  deduce  from  these 
physiological  data  for  the  explanation  of  the  great  waste 
of  nervous  energy  brought  about  by  certain  exercises 
which  only  represent  a  moderate  expenditure  of  muscular 
energy,  but  which  demand  an  instantaneous  obedience 
of  the  muscles  to  the  orders  of  the  will  :  fencing  for 
example. 


CHAPTER  II. 

MOVEMENTS. 

Associated  Action  of  Different  Regions  during  Work — How  a 
Blow  is  given  with  the  Fist— Coordination  of  Movements  ; 
Antagonistic  Muscles  ;  the  Muscular  Sense — Ataxic  Patients — 
Static  Contraction — Stiffness  in  Exercises — Muscular  Educa- 
tion, Association  of  the  great  Organic  Functions  with 
Muscular  Movement — Effort — The  Porter  and  his  Load — 
Effort  during  Slight  Expenditure  of  Force  ;  too  Hard  a  Nut — • 
Frequency  of  Effort  in  Exercise — Long-Distance  and  Sprint 
Running.  Influence  of  Movements  on  the  Circulation — The 
Quickening  of  the  Pulse  ;  its  Mechanism — The  Pulmonary 
Circulation  and  the  Active  Congestion  of  the  Lungs — Con- 
giestion  of  the  Brain  during  Movement — Dancing  Dervishes — 
A  Runaway  Horse, 

I. 

The  slightest  movement  performed  by  the  human 
machine  needs  the  employment  of  a  great  number  of 
wheels.  When  a  muscle  contracts,  the  neighbouring 
muscles  always,  and  distant  ones  sometimes,  act  with  it, 
and  are  associated  in  its  work. 

Let  us  analyse  the  phenomena  of  a  very  simple 
movement 

In  order  to  be  able  to  move  the  forearm,  the  arm 
must  be  fixed  to  give  a  point  of  application.  The  arm 
itself  must  be  supported  by  the  shoulder,  and  the 
shoulder  by  the  vertebral  column  and  the  thorax.  But 
the  thorax  and  vertebral  column  being  supported  by 
the  pelvis,  and  this  by  the  lower  extremities,  the  whole 
body  is  obliged  to  associate  in  the  movement  of  the 
forearm.  From  head  to  foot,  all  the  muscles  participate 
in  the  most  insignificant,  and  most  localised  woik. 


MOVEMENTS.  21 

The  slightest  movement  has  a  tendency  to  displace 
the  centre  of  gravity  of  the  body.  While  the  extremi- 
ties are  at  ^^•ork,  the  vertebral  column,  a  long  bony  rod 
which  forms  the  axis  of  the  body,  oscillates  like  the 
beam  of  a  balance,  to  right  or  to  left,  forwards  or  back- 
wards, to  compensate  for  the  displacement  occasioned 
by  the  burthen  raised  or  the  movement  performed. 

The  lower  limbs  almost  always  associate  in  the  move- 
ments of  the  upper  limbs,  and  in  many  cases,  a  man 
really  derives  from  his  legs  the  force  which  seems  to 
come  from  his  arms. 

"  When  I  had  my  two  legs,"  said  a  Zouave  from  whom 
they  had  been  cut  off,  "  I  used  to  give  a  splendid  blow 
with  my  fist  !  "  And  the  Zouave  was  right.  A  well 
delivered  blow  with  the  fist  is  supported  by  the  whole 
body.  The  effort  which  thrusts  forward  the  closed 
hand  begins  in  the  leg,  which  is  extended,  and  then  in- 
volves the  thigh  which  projects  the  trunk  in  the  direction 
in  w^hich  the  blow  is  delivered  ;  the  muscles  of  the  loins 
transmit  the  movement  to  the  thorax,  and  those  of  the 
thorax  pass  it  on  to  the  shoulder,  which  in  its  turn 
thrusts  forward  the  forearm,  and  the  fist,  transmitting 
to  them  the  force  to  which  the  whole  body  has  con- 
tributed. 

In  this  manner  every  muscular  movement  may  have 
an  influence  at  a  point  very  far  distant  from  that  to 
which  it  seems  to  be  localised.  Hence  an  exercise 
sometimes  produces  very  marked  effects  in  a  region  of 
the  bod}^  in  which  we  should  not  have  dreamed  of  look- 
ing for  them 

The  muscles  of  a  whole  limb  almost  always  act  all 
together  in  the  performance  of  a  movement,  although 
in  each  limb  one  half  of  the  muscles  generally  has  an 
action  diametrically  opposed  to  that  of  the  other  half. 
In  the  forearm,  the  muscles  of  the  anterior  surface  have 
the  function  of  flexing  the  fingers  and  closing  the  hand; 
they  are  flexors.  Those  of  the  posterior  surface  are  ex- 
tensors, and  the  action  is  to  open  the  hand.  For  this 
reason  these  two  sets  of  muscles  are  called  antagonists. 

In  the  performance  of  a  movement,  no  muscle  ever 


22  PHYSIOLOGY  OF  BODILY  EXERCISE. 

acts  without  a  corresponding  contraction  of  its 
antagonist,  which  submits  it  to  a  kind  of  balance  and 
control.  This  opposition  is  necessary  to  moderate, 
direct,  and  make  accurate  the  movement. 

When  two  men  are  wheeHng  a  barrow  down  a  hill, 
and  the  one  in  front  pulls  forwards,  and  the  one  behind 
backwards,  we  may  say  that  the  action  of  the  first  is 
antagonistic  to  that  of  the  second.  Their  efforts  in 
different  directions  are  combined  in  order  that  the 
barrow  may  advance  neither  too  slowly  nor  too  quickly, 
and  may  go  at  a  uniform  pace.  In  the  same  way  two 
antagonistic  muscles  regulate  each  other  ;  when  they 
oppose  each  other  in  a  proper  measure,  the  movements 
are  precise  and  well  co-ordinated. 

Co-ordination  of  movements  is  perfected  by  exercise, 
but  it  is  often  instinctive  and  perfect  from  the  time  of 
birth  in  the  performance  of  certain  natural  actions. 
The  chicken  hardly  out  of  the  ^gg,  reaches  with  the 
first  stroke  of  its  beak  the  grain  of  corn  it  sees,  and  the 
infant  needs  no  practice  to  learn  the  degree  of  contrac- 
tion of  the  lips  and  tongue  necessary  in  the  act  of 
sucking. 

For  the  movements  of  an  exercise,  however,  it  is 
sometimes  necessary  to  go  through  a  long  apprentice- 
ship. Much  practice  is  necessary  before  a  pianist  is 
able  to  place  his  finger  on  the  desired  note  with  an  ease 
equal  to  that  which  the  chicken  puts  its  beak  to  a  grain 
of  corn.  Thanks  to  the  imiscular  sense  we  can  educate 
antagonistic  muscles,  and  succeed,  after  more  or  less 
practice,  in  making  them  act  with  perfect  harmony. 

The  muscular  sense  is  the  feeling  we  have  of  the 
force  with  which  a  muscle  contracts  and  the  direction  in 
which  it  acts.  It  is  the  muscular  sense  which  enables 
us  to  place  the  hand  or  the  foot  on  the  precise  point 
which  we  wish  to  touch.  By  means  of  it  we  regulate 
the  expenditure  of  muscular  force  in  proportion  to  the 
resistance  to  be  overcome.  This  sense  guides  us  in- 
dependently of  vision,  and  enables  us  to  reach,  with  our 
eyes  closed,  objects  the  position  of  which  is  exactly 
known  to  us  :  different  parts  of  our  body,  for  instance. 


MOVEMENTS.  23 

There  îs  a  disease  characterised  by  the  abolition  of 
the  muscular  sense,  and  by  defective  co-ordination  of 
movements  ;  this  is  locomotor  ataxy.  The  ataxic  man 
does  not  know  how  to  give  to  his  muscles  an  impulse 
suitable  to  the  movement  required.  If  he  wishes  gently 
to  take  up  an  object,  his  hand  passes  by  it,  or  strikes 
and  upsets  it.  If  he  wishes  to  walk  a  few  steps,  his  legs 
are  violently  projected  forwards,  to  the  side,  or  upwards. 
He  has  the  aspect  rather  of  an  individual  desirous  of 
kicking  someone  with  his  foot,  than  of  one  who  wishes 
to  walk. 

A  nimble  man,  by  the  use  of  his  muscular  sense,  can 
perform  the  most  surprising  feats.  The  skill  of  jugglers 
and  balancers  is  due  to  the  cultivation  of  this  sense, 
and  to  the  education  of  antagonistic  muscles. 

In  all  forms  of  bodily  exercise,  antagonistic  muscles 
play  a  most  important  part,  and  it  is  impossible  to 
understand  certain  phenomena  of  fatigue,  without 
taking  their  action  into  account.  Just  as  much  as  an- 
tagonistic muscles  facilitate  movement  when  their  action 
is  exact  and  moderate,  so  m.uch  can  they  hinder  it  when 
they  act  in  an  exaggerated  or  unsuitable  manner. 

Let  us  suppose  that  the  flexors  and  extensors  of  the 
arm  contract  with  an  equal  energy,  the  limb  drawn  by 
two  equal  forces  in  two  opposite  directions  will  remain 
motionless.  We  can  easily  understand  that  this  immo- 
bility is  not  that  of  repose.  It  is  contracture  or  static 
contraction,  so  called  in  contradistinction  to  the  dynamic 
contraction  which  accompanies  movements.  It  has  been 
proved  that  static  contraction  produces  greater  fatigue, 
and  causes  a  more  immediate  rise  in  the  temperature  of 
a  muscle  than  dynamic  contraction.* 

In  common  language,  static  contraction  is  called  stiff- 
ness. In  bodily  exercises,  exaggerated  and  ill-planned 
contractions  of  antagonistic  muscles  produce  stiffness  of 
the  movements.  It  is  the  fault  of  all  beginners,  and  the 
sign  of  inexperience  in  skilled  labour.  "  Don't  keep 
your  fingers  so  stiff,"  we  say  to  a  young  pianist    "  Your 

•  Béclard     Physiologic. 


24  PHYSIOLOGY  OF   BODILY   EXERCISE. 

wrist  is  not  pliable  enough,"  says  the  fencing-master  to 
his  pupil.  We  demand  ease  of  the  horseman,  and  we 
forbid  a  rower  to  be  stiff. 

A  man  unskilled  in  the  exercise  he  is  doing,  expends 
two  or  three  times  the  necessary  amount  of  force. 
Hence  a  difficulty  in  estimating  the  real  quantity  of 
work  done  ;  and  the  doctor,  in  prescribing  exercise, 
must  always  take  into  consideration  the  muscular  edu- 
cation of  his  patient. 

It  is  necessary  to  have  personal  experience  of  bodily 
exercise  to  estimate  the  economy  of  labour  which 
results  from  a  well  co-ordinated  movement.  Muscular 
expenditure  is  not  dimiinished  in  skilled  exercises  alone  ; 
it  becomes  less  also  in  exercises  which  seem  to  call 
for  nothing  but  brute  force  :  the  act  of  raising  a  weight, 
for  instance. 

All  movements  need  an  apprenticeship,  because,  as 
we  said  in  the  beginning,  there  are  no  isolated  move- 
ments. One  limb  assists  another,  and  the  attitude  of 
the  body  helps  or  hinders  the  play  of  the  legs  and  arms. 

In  order  that  all  parts  which  associate  in  the  per- 
formance of  a  movement,  may  have  a  really  useful  share 
in  it,  there  must  be  a  kind  of  discipline,  assigning  to 
each  muscle  its  particular  part.  The  Will,  which  com- 
mands, has  under  its  orders  a  number  of  agents  which 
cannot,  at  the  first  attempt,  easily  be  made  to  act 
together.  The  man  who  exercises  his  muscles,  is  like 
the  general  who  drills  his  troops,  in  order  to  have  them 
under  control  on  the  day  of  battle. 

Thus  is  explained  the  apparent  increase  of  muscular 
power  after  certain  exercises.  There  is,  certainly,  a  real 
increase  in  the  contractile  force  of  a  muscle  which  is  at 
work  every  day,  but  this  increase  seems  often  so  rapid, 
that  we  should  be  embarrassed  for  an  explanation,  if  we 
did  not  consider  the  influence  of  educa'-ion,  or,  as  we 
might  say,  drilL 


MOVEMENTS.  2$ 


IT. 

When  a  man  is  raisin^^  a  heavy  load  from  the  ground, 
we  see  his  breathing  stop,  his  face  redden,  and  the  veins 
of  his  forehead  and  neck  swell.  It  looks  as  if,  at  the 
moment  of  greatest  expenditure  of  bodily  force,. an  in- 
visible cord  were  tightened  round  his  neck,  stopping  at 
once  the  entry  of  air  into  the  lungs,  and  the  circulation 
of  the  blood  in  the  veins. 

The  phenomena  which  accompany  a  very  energetic 
muscular  action,  are  in  fact  very  like  those  which  would 
result  from  a  constriction  of  the  throat  during,  the  first 
stage  of  strangulation.  Every  time  an  effort  is  made, 
the  air  passages  are  closed  and  the  veins  in  the  thorax 
compressed. 

The  porter  who  wishes  to  raise  a  load  on  to  his 
shoulders,  first  grasps  it,  and  then,  before  raising  it  from 
the  ground,  he  stops  for  a  moment  as  if  to  prepare 
himself  for  the  movement.  This  short  period  is  occupied 
by  important  preliminaries. 

Before  performing  the  movement,  he  must  take  a 
deep  breath.  A  great  quantity  of  air  is  drawn  into  the 
lungs,  and  the  glottis  immediately  closed  to  prevent  its 
exit.  The  chest  expands.  The  ribs  are  thus  everted 
and  raised,  but  at  the  same  moment  there  is  an 
enero-etic  contraction  of  the  abdominal  muscles  which 
tends  to  depress  them.  The  air  in  the  chest  thus 
undergoes  a  vigorous  compression,  and  the  walls  of  the 
thorax,  pushed  upwards  on  the  one  hand,  and  pulled 
downwards  on  the  other,  are  rendered  motionless  by  the 
simultaneous  action  of  the  two  opposite  forces  to  which 
they  are  exposed. 

The  fixing  of  the  thoracic  walls  is  the  object  of  this 
strife  between  the  antagonistic  forces  of  respiration,  in 
which  the  inspiratory  muscles  are  opposed  to  the  expi- 
ratory, and  which,  in  physiological  language,  is  known 
as  effort.  The  ribs,  being  motionless  for  the  moment, 
can  give  a  fixed  and  solid  point  of  application  to  all  the 


26  UlYSIOLOGY  OF   BODILY  EXERCISE. 

muscles  attached  to  them,  and  in  particular  to  the  great 
muscular  masses  which  move  the  arms,  the  vertebral 
column  and  the  pelvis  ;  these  muscles  then  contract 
vigorously  and  the  load  is  raised. 

As  soon  as  the  muscular  action  is  completed,  the  chest 
empties  itself.  The  air  which  was  retained  is  briskly- 
expelled,  with  the  production  of  a  kind  of  murmuring 
sigh  which  indicates  the  end  of  the  effort. 

Effort  is  a  physiological  action  which  consists  in  the 
association  of  a  great  number  of  muscles  and  bones, 
that  they  may  assist  in  the  same  movement,  and  which, 
moreover,  brings  into  active  association  with  the  mus- 
cular work  two  great  functions  of  the  economy  :  respi- 
ration and  circulation. 

Effort  is  generally  considered  to  be  a  phenomenon 
intimately  connected  with  very  great  expenditure  of 
force.  It  may,  however,  often  come  into  play  in  cases 
in  which  the  work  done  is  very  trifling.  The  essential 
condition  for  the  production  of  effort  is  the  need  of 
giving  to  tho  contraction  of  a  group  of  muscles  all  the 
force  of  which  this  group  is  capable. 

Whenever  a  man  wishes  to  put  into  a  muscular  action, 
however  localised  it  may  be,  his  whole  strength,  the 
action  is  inevitably  accompanied  by  a  series  of  physiolo- 
gical phenomena,  of  which  the  final  result  is  the  suspen- 
sion of  the  respiratory  movements. 

Watch  a  man  trying  to  crack  a  nut  between  his  finger 
and  thumb.  If  the  fingers  are  very  vigorous,  and  the 
shell  offers  little  resistance,  the  muscular  contractions 
remain  localised  to  the  forearm,  and  there  is  no  de- 
rangement of  the  normal  functions  of  other  organs. 
The  countenance  remains  calm,  and  the  respiration  is 
undisturbed  ;  the  nut  is  cracked  without  effort.  But  if 
the  shell  holds  out,  and  the  man  has  to  use  all  his  force, 
we  see  the  muscular  contraction  extend  to  the  arm,  the 
shoulder,  and  finally  the  neck,  chest,  and  abdomen. 
Respiration  ceases,  the  face  becomes  congested,  the  veins 
of  the  forehead  and  neck  fill  and  become  prominent  ; 
and  when  the  nut  is  at  last  cracked,  there  is  a  kind  of 


MOVEMENTS.  2^ 

sigh,  similar  to  that  of  the  porter  who  has  raised  a  load 
from  the  ground. 

It  seems  surprising  at  first,  that  an  action  in  which 
the  flexors  of  the  fingers  are  the  only  muscles  directly 
concerned,  should  necessitate  the  contraction  of  far 
distant  muscles,  and  we  fail  to  understand  why,  in  order 
to  shut  the  hand  with  all  possible  energy,  a  contraction 
of  the  abdominal  muscles  is  necessary. 

The  body  is  made  up  of  a  number  of  moveable  pieces, 
and  a  muscle  cannot  exercise  all  its  contractile  force 
unless  one  of  its  extremities  be  attached  to  a  fixed 
point.  Hence  it  is  necessary,  if  we  wish  to  move  the 
forearm.,  that  the  arm  should  be  fixed  at  the  shoulder 
joint,  that  the  shoulder  should  not  move  on  the  thorax, 
nor  the  latter  on  the  pelvis.  The  lungs  filled  with  air 
form  a  kind  of  resistant  cushion,  against  which  the 
abdominal  muscles  strongly  press  the  ribs  by  pulling 
them  downwards. 

Thus,  by  a  chain  of  successive  muscular  contractions, 
movements  localised  in  the  extremities  of  the  limbs,  can 
demand  the  assistance  of  the  abdominal  muscles  and  the 
ribs,  and  finally  bring  about  a  compression  of  the  tho- 
racic and  abdominal  viscera,  in  a  word,  all  the  results  of 
effort. 

Effort,  so  complex  a  phenomenon,  associating  the 
great  organic  functions  with  the  most  localised  muscular 
action,  results  from  the  impossibility  of  fixing  one  of 
the  bones  of  the  extremities  unless  all  the  bones  of  the 
trunk  are  quite  motionless.  Its  object  is  to  make  of  the 
neck,  thorax,  and  pelvis  a  rigid  and  resistant  whole,  to 
solder  into  one  piece  the  jointed  system  which  the  trunk 
constitutes. 

A  profound  disturbance  always  occurs  in  the  system 
during  effort,  for  this  act  always  momentarily  hinders 
respiration  and  circulation. 

The  lung  serves  to  fix  the  ribs,  and  undergoes  a  com- 
pression proportionate  to  the  intensity  of  the  work. 
The  first  result  of  this  energetic  compression  is  the 
distension  of  the  air-filled  pulmonary  vesicles,  and  hence 


28  PHYSIOLOGY  OF   BODILY  EXERCISE. 

there  is  a  possibility  of  their  rupture.  But  the  lun<^ 
itself  transmits  the  compression  to  which  it  is  subjected 
to  the  neighbouring  organs,  the  great  vessels,  and  the 
heart.  The  blood  is  forced  back  in  the  venae  cavae, 
and  regurgitates  into  the  peripheral  veins,  which  swell 
and  become  prominent  in  the  neck  and  forehead.  The 
capillaries  are  engorged  with  blood,  and  the  circulation 
is  momentarily  arrested  in  the  heart,  the  lungs,  and  the 
other  organs. 

The  great  arteries,  and  the  heart  itself,  also  are  in- 
fluenced by  effort  ;  the  calibre  of  the  aorta  may  be  for 
the  moment  effaced,  and  the  beat  of  the  heart  arrested 
for  an  instant  by  the  pressure.  The  blood-pressure  is 
greatly  increased  in  the  veins  and  arteries  while  the 
effort  lasts.  Indeed,  we  often  see  prolonged  efforts  give 
rise  to  a  rupture  of  venous  capillaries,  and  even  to  lace- 
ration of  veins  of  a  considerable  size.  In  the  most 
moderate  efforts  blood-stasis,  a  momentary  passive  con- 
gestion of  internal  organs,  is  unavoidable, 

III. 

The  mechanism  of  effort  has  shown  us  how  difficult  it 
is  for  the  great  organic  functions  to  isolate  themselves 
from  the  work  of  the  muscles,  when  the  latter  contract 
very  energetically.  But  it  is  unnecessary  that  the  work 
should  be  intense,  and  that  an  effort  should  occur,  in 
order  that  the  whole  system  should  be  influenced  by 
muscular  contraction.  We  are  about  to  see  that  bring- 
ing muscles  into  action  always  produces  important  modi- 
fications in  the  processes  of  the  great  organic  functions, 
and  this  however  moderate  the  muscular  action. 

If  we  observe  the  circulation  in  the  arteries  of  a 
muscle  performing  work,  we  perceive  that  the  blood  is 
flowing  with  a  greater  activity  than  during  repose.  This 
is  the  result,  however  small  the  work  done,  and  however 
small  the  muscle  concerned. 

Thus,  if  a  special  registering  instrument  be  fitted  to 
the  nutrient  artery  of  the  inasseter  muscle  of  a  horse., 
and  we  aote  the  rapidity  of  the  blood   current  at  dif- 


MOVEMENTS.  29 

ferent  moments,  wc  remark  a  very  manifest  acceleration 
of  the  current  at  the  moment  when  the  animal  puts  the 
muscle  in  action,  as  in  chewing  oats.  There  is  a  more 
considerable  flow  of  blood  to  the  organ  in  action,  and 
the  debit  of  its  nutrient  artery  is  increased. 

But  this  is  not  all.  The  acceleration  noted  in  the  vas- 
cular region  which  supplies  blood  to  the  muscle  is  pro- 
pagated gradually  to  the  great  vessels,  then  to  the  heart 
and  to  the  entire  circulatory  S3^stem.  After  some 
minutes  the  blood  is  flowing  in  all  the  arteries,  even 
in  those  most  remote  from  the  head,  with  the  same 
speed  as  in  those  of  the  masseter  muscle,  and  in 
the  end  the  circumscribed  movements  of  mastication 
will  be  found  to  have  caused  a  more  frequent  pulse. 
We  can  understand  that  this  effect  will  be  more 
prompt  and  more  intense  when  the  movement,  instead 
of  being  confined  to  a  small  group  of  contractile  fibres, 
involves  powerful  muscular  masses,  as  in  violent  exercises. 

The  increased  frequency  of  the  pulse  during  work 
results  from  a  sort  of  aspiration  of  blood  towards  the 
muscles  undergoing  contraction.  It  is  a  vital  law  that 
every  organ  in  activity  draws  towards  it  a  greater 
quantity  of  nutrient  fluid  than  it  does  when  in  a  state  of 
repose.  This  law  has  been  verified  even  in  regard  to  the 
secreting  glands.  We  cannot  enter  into  the  intimate 
explanation  of  this  phenomenon  ;  suffice  it  to  say  that  it 
is  invariable,  and  that  every  stimulus  of  a  vital  function 
causes  a  flow  of  blood  towards  the  organ  thrown  into 
activity.  Ubi  stimulus^  ibi  fluxus.  This  is  a  formula 
which  expresses  the  fact  without  explaining  it. 

Thus  the  excitement  produced  by  the  nervous  flow  to 
the  contractile  fibre  draws  to  the  muscle  a  greater  quan- 
tity of  blood,  and,  in  order  to  supply  this  increase,  the 
blood  flows  more  quickly  towards  the  excited  organ. 
The  increased  frequency  of  the  pulse  is  a  physiological, 
not  a  mechanical,  phenomenon,  as  at  first  sight  we  are 
inclined  to  think.  It  is  not  the  pressure  of  the  muscles 
swollen  by  contraction  which  quickens  the  circulation 
in  the  arteries  :  it  is  rather  a  kind  of  aspiration  by  the 
muscles,  which  have  become  more  thirsty  for  blood. 
4 


30  PHYSIOLOGY  OF  BODILY  EXERCISE. 

This  explanation  is  confirmed  by  the  indications  of  a 
manometer  connected  with  an  artery.  Tlie  instrument 
shows  a  fall  of  pressure  in  the  vessel  at  the  moment  of 
work.*  The  pressure  would  rise,  on  the  other  hand,  if 
the  acceleration  were  due  to  a  driving  back  of  blood  by 
the  muscles. 

Muscular  contraction  may,  however,  be  called  into  play 
as  a  mechanical  cause,  capable  of  quickening  the  blood 
current  in  the  veins  and  capillaries.  The  compression 
resulting  from  the  swelling  of  muscles  in  action  may  thus 
become  a  factor  in  the  acceleration  of  the  blood  current 
during  work.  In  any  case,  however,  this  is  merely  an 
accessory  factor. 

Whatever  the  cause,  the  quickening  of  the  blood  cur- 
rent during  exercise  is  a  constant  phenomenon.  Con- 
stantly, therefore,  at  this  time,  the  organs  are  traversed 
by  a  greater  quantity  of  blood.  There  is  an  active  con- 
gestion of  all  the  organs  during  violent  exercise  :  hence 
more  active  performance  of  function. 

It  will  not  be  devoid  of  interest,  after  considering  the 
phenomena,  to  study  the  consequences  of  the  active  con- 
gestion which  accompanies  every  energetic  movement. 
This  active  congestion  is  the  really  useful  period  of 
bodily  exercises,  that  to  which  they  owe  their  forti- 
fying power.  A  man  during  this  period  of  hyper- 
activity of  all  his  organs  benefits  from  a  consider- 
able increase  of  his  nutritive  forces.  All  the  organs 
and  all  the  tissues  of  the  body  are  the  seat  of  a 
more  active  circulation,  and  we  know  that  the  nutri- 
tion of  an  organ  is  in  proportion  to  the  quantity 
of  blood  which  passes  through  it. 

Under  the  influence  of  the  greater  quantity  of  blood 
which  traverses  the  lung,  this  organ,  fellow-worker  with 
the  heart,  becomes  more  active,  and  introduces  into  the 
system  a  greater  quantity  of  air.  The  vital  combus- 
tions, thanks  to  this  freer  supply  of  oxygen,  are  more 
energetic  and  more  complete.  If  we  may  make  a  simple 
comparison,  exercise  increases  the  intensity  of  the  vital 

•  ChauveaUj  Comptes  rendus  de  V Académie  des  Sciences^  1857. 


MOVEMENTS.  31 

combustions,  just  as  lowering  the  blower  of  a  fire-place 
makes  the  combustion  of  the  wood  more  active  by  in- 
creasing the  draught. 

The  duration  of  this  salutary  period  of  exercise  varies 
with  different  individuals.  With  some  persons  a  con- 
siderable muscular  expenditure  is  necessary  to  bring 
about  this  expansion  of  the  vital  forces  due  to  active 
congestion  :  these  are  the  strong  natures,  and  those 
accustomed  to  exercise.  With  feeble  natures,  in  persons 
accustomed  to  complete  rest,  and  to  muscular  inaction, 
the  least  movement,  the  shortest  walk,  produces  a  similar 
result.  The  student  calls  a  game  of  billiards  exercise  ; 
for  the  pugilist  who  is  training  for  a  prize-fight,  the 
use  of  dumb-bells  is  a:i  exercise  which  employs  without 
fatiguing  him. 

Perhaps  the  most  interesting  effect  of  this  active  con- 
gestion of  the  organs  under  the  influence  of  bodily 
exercise  is,  that  experienced  by  the  brain.  All  thinkers 
have  noticed  that  physical  exercise  is  favourable  to 
brain-work.  The  Peripatetics  disputed  while  walking, 
and  found  their  arguments  more  easily  when  the  body 
was  warmed  by  exercise.  "  Walking  and  movement," 
said  J.  J.  Rousseau,  "favour  the  action  of  the  brain  and 
the  work  of  thinking." 

Stimulation  of  the  brain  mav^  be  very  qreat  under  the 
influence  of  active  congestion  brought  about  by  muscular 
action.  It  is  possible  to  be  made  drunk  by  movement, 
and  in  certain  brains  predisposed  either  by  their  native 
organisation,  or  by  exalted  ideas  or  passions,  muscular 
exercise  is  often  the  prelude  to  actions  resembling  those 
of  intoxication  and  even  of  madness.  The  war-dances 
of  savages,  the  contortions  of  dancing  dervishes,  pro- 
duce without  the  assistance  of  any  alcoholic  drink,  a  state 
of  cerebral  hyperexcitement  capable  of  bringing  about 
the  most  violent  nervous  phenomena. 

It  is  related  that  the  Gauls,  in  the  midst  of  the  excite- 
ment of  battle,  were  sometimes  seized  with  a  sort  of 
intoxication  which  made  them  furious  and  insensible 
to  wounds. 

Without  going  as  far  as  intoxication,  exercise  in   the 


32  PHYSIOLOGY  OF  EODILY  EXERCISE. 

end  produces  in  every  one  a  slight  excitement,  a  kind 
of  animation.  The  young  girl  dancing  becomes  ani- 
mated, and  would  spend  night  and  day  forgetful  of 
fatigue  :  a  quarter  of  an  hour's  waltzing  puts  her  .into 
the  same  condition  as  does  a  glass  of  champagne.  A 
vigorous  horse  becomes  animated  by  a  gentle  gallop, 
and  sometimes  becomes  so  excited  as  to  be  attacked  by 
a  kind  of  madness,  and  runs  away. 

All  these  phenomena  result  from  a  moderate  cerebral 
congestion.  The  apparent  effects  of  exercise  on  the 
individual  are,  in  short,  similar  to  those  produced  by 
alcohol  :  the  same  flush,  the  same  bright  eyes,  the  same 
active  demeanour. 

Exercise  has  a  stimulating  action  on  all  the  organic 
functions,  because  it  renders  the  circulation  in  all  the 
organs  more  active.  The  blood  makes  all  parts  of  the 
system  share  in  the  stimulation  which  the  will  has  sent 
to  the  muscles  to  put  them  in  action,  and  this  stimula- 
tion is  the  more  marked  because  the  blood  is  warmed 
by  the  friction  against  the  walls  of  the  vessel  through 
which  it  flows  more  rapidly,  and  warm  blood  is  more 
stimulating. 

Thus,  when  the  limbs  move,  the  internal  organs  cannot 
remain  inert,  and  the  whole  organism  performs  its  func- 
tions with  more  energy  under  the  influence  of  muscular 
contraction. 


CHAPTER  III. 

HEAT. 

The  Human  Motor  and  Heat-Engines.  The  Mechanical  Equiva- 
lent of  Heat — Heat  is  a  Cause  of  Movement,  not  its  Effect 
— Heat  Lost — How  the  Temperature  of  the  Body  is  regulated 
— Effects  of  Heat  on  Muscle — Experiment  of  Marey  on  Caout- 
chouc— Observation  of  Daily  Phenomena — Muscle  Heated  and 
Muscle  Numbed  by  Cold  — Gestures  of  Anger — Why  we  Make 
preliminary  Passes  in  Fencing — The  Hare  which  has  just  been 
put  up — Effects  of  too  high  a  Temperature — Death  of  Muscle 
at  +  45°  C. 

I. 

The  human  body  has  been  compared,  inasmuch  as  it 
is  a  source  of  motion,  to  a  machine  driven  by  heat.  We 
know  that  no  machine  creates  force.  The  most  perfect 
motors  do  nothing  more  than  transform  one  force  into 
another.  The  human  motor  transforms  heat  into  move- 
ment. 

In  the  steam  engine  it  is  easy  to  trace  the  connection 
between  cause  and  effect.  The  movement  of  the  wheels  is 
due  to  a  rod  set  in  action  by  the  piston  ;  the  piston  moves 
on  account  of  the  pressure  of  steam,  and  the  latter  owes 
its  expansile  force  to  the  heat  which  it  has  absorbed. 
Finally  the  heat  itself  is  due  to  the  combustion  of 
carbon.  The  combustion  of  carbon  is  found  on  analysis 
to  be  the  cause  of  the  movement  of  the  locomotive. 

In  the  body  the  motor  power  of  the  muscles  comes 
neither  from  the  nerves,  the  spinal  cord,  nor  the  brain. 
We  know  that  these  three  organs  only  transmit  to  the 
muscles  the  stimulus  of  the  will.  The  will  itself  is  not 
the  source  of  the  motor  force  ;  it  orders  the  movement 
and  sets  the  machine  in  action,  just  as  the  driver  gives 
the  first  impulse  to  the  locomotive  by  opening  the  steam* 


34  PHYSIOLOGY  OF   BODILY   EXERCISE. 

valve.  But  it  would  be  as  absurd  to  say  that  the  will 
produces  the  muscular  force,  as  to  attribute  to  the  driver 
the  strength  and  swiftness  of  his  machine. 

The  initial  fact  and  the  indispensable  condition  of 
movement  in  the  human  body,  just  as  in  all  other  heat- 
engines,  is  the  production  of  heat.  The  body  produces 
heat  by  the  combustion  of  its  own  materials. 

The  combustion  of  our  tissues  is  an  expenditure 
necessitated  by  movement.  How  is  this  expenditure 
employed  and  how  does  the  muscle  make  use  of  the 
heat  produced  ?  This  problem  is  far  from  being  solved, 
but  we  know  that  in  the  body,  as  in  the  machine,  there 
is  an  intimate  connection  and  a  constant  relation  between 
the  quantity  of  heat  expended  and  the  amount  of  work 
done.  Muscular  work  is,  like  the  work  of  all  thermo- 
dynamic apparatus,  subject  to  the  principle  of  the 
fitechan ical  eqit ivalen t  of  Jieat. 

In  mechanics,  work  is  measured  by  a  unit  called  the 
kUogrammetre^  and  heat  by  a  unit  called  the  calory. 
The  kilogrammetre  is  the  quantity  of  work  necessary  to 
raise  a  weight  of  one  kilogramme  through  a  height  of  one 
metre,  and  the  calory  is  the  quantity  of  heat  necessary  to 
raise  the  temperature  of  a  kilogramme  of  water  one 
degree  centigrade. 

Physicists  tells  us  that  the  mechanical  equivalent 
of  heat  is  425  kilogrammetres.  That  is  to  say,  the 
quantity  of  heat  necessary  to  raise  the  temperature  of  a 
kilogramme  of  water  from  0°  C.  to  i*"  C.  would  be  capable, 
when  transformed  into  work,  of  raising  a  weight  of  425 
kilogrammes  through  a  height  of  one  metre. 

Such  is  the  theory  ;  but  in  practice  there  is  always 
much  work  lost,  and  the  most  perfect  apparatus  hardly 
makes  use  of  nine  or  ten  per  cent,  of  the  heat  produced  : 
the  rest  is  lost  in  the  machine,  which  becomes  heated. 
In  the  human  body,  the  heat  lost,  from  the  point  of  view 
of  work,  is  considerable,  and  as  the  body  absorbs  that 
which  is  not  used,  its  temperature  is  raised  during 
muscular  exercise. 

Considering  the  enormous  quantity  of  heat  lost  during 
muscular  work,  it  is  at  first  sight  astonishing  that  the 


HEAT.  35 

body  in  which  so  much  heat  is  distributed,  does  not 
rise  to  a  higher  temperature.  As  a  matter  of  fact,  we 
find  that  the  temperature  of  a  man  doing  violent  work 
is  only  i°  C.  or  2°  C.  higher  than  that  of  a  man  at  rest. 

This  constancy  in  the  temperature  of  the  human  body 
is  due  to  a  regulating  mechanism  with  which  the  system 
is  provided  and  which  works  in  the  following  manner. 

When  the  body  is  warmed,  the  superficial  blood- 
vessels dilate  and  receive  a  greater  quantity  of  blood 
drawn  from  the  internal  organs.  Thus  we  always  see 
the  skin  of  a  hot  man  redden  and  swell.  The  blood 
which  passes  through  the  skin  cools  very  quickly  by 
radiation,  and,  since  the  circulation  is  very  active  in  the 
body  of  a  person  doing  work,  the  liquid  which  has  given 
up  its  heat  soon  has  its  place  taken  by  another  wave  of 
blood  which  becomes  cool  in  its  turn.  In  a  few  minutes 
all  the  blood  in  the  system  has  been  thus  exposed  at 
the  surface  of  the  body. 

The  surface  of  the  skin  considered  as  a  means  of 
refrigeration,  does  not  only  radiate  heat,  but  also  makes 
use  of  the  evaporation  of  cutaneous  perspiration.  Every 
one  knows  the  cooling  power  of  an  evaporating  liquid. 
Everyone  can  also  confirm  the  comfort  derived  from 
sweating  when  working  at  a  high  temperature. 

Where  there  is  exce=:sive  cooling,  the  mechanism  is 
the  opposite  to  that  which  we  have  just  described.  The 
capillaries  contract  under  the  influence  of  cold,  and  their 
calibre  is  lessened,  driving  the  mass  of  blood  forcibly 
into  the  internal  organs.  In  the  depth  of  the  tissues 
the  blood,  protected  from  the  external  cold,  can  preserve 
its  heat. 

It  is  commonly  said  that  work  produces  heat  in  the 
body  ;  but  the  opposite  is  the  truth  :  the  heat  is  the 
cause  and  not  the  effect  of  the  work.  It  is  necessary  to 
supply  heat  to  a  steam-engine  in  order  to  make  it  do 
work,  and  a  considerable  time  elapses  from  the  moment 
when  the  fire  is  lighted  to  that  when  the  locomotive 
starts.  In  our  system  the  affair  is  not  such  a  long  one, 
but  the  work  is  not  absolutely  instantaneous,  and  there  is 
always  an  appreciable  interval  between   the  willing  and 


36  PHYSIOLOGY  OF  BODILY  EXERCISE. 

the  performance  of  a  movement.  This  period  is  occupied 
by  a  series  of  operations  in  which  combustions,  the 
source  of  vital  heat,  hold  their  place. 

Muscular  contraction  cannot  occur  without  the  pro- 
duction of  heat.  If  we  bury  in  a  muscle  a  needle 
connected  with  a  thermo-electric  apparatus,  and  make 
the  muscle  contract,  a  rise  of  temperature  is  at  once 
indicated. 

Common  phenomena  confirm  scientific  experiments. 
Everyone  knows  that  he  can  warm  himself  by  move- 
ments, and  cold  stimulates  everyone  to  quicken  his  pace 
and  provide  for  the  formation  of  heat. 

We  know  the  importance  of  heat  in  the  production  of 
movement,  but  we  are  ignorant  how,  and  in  what 
manner,  heat  acts  on  muscle  and  makes  it  contract. 
Does  it  act  directly  on  the  contractile  fibres  and  make 
them  shorten  mechanically,  as  it  does  certain  elastic 
substances  ?  Some  physiologists  are  inclined  to  think 
this. 

"When  we  warm  a  muscle  it  changes  its  shape,  and 
we  see  it  shorten  and  swell.  These  effects  disappear  on 
cooling  the  muscle. 

"  Muscle-fibres  are  not  alone  in  possessing  this  power 
of  changing  heat  into  work.  Caoutchouc,  for  example, 
behaves  in  a  similar  manner  ;  it  is  even  possible  with 
this  substance  to  imitate  up  to  a  certain  point  muscular 
phenomena. 

"  If  we  take  a  piece  of  a  thread  of  unvulcanised  caout- 
chouc, and  if  by  drawing  it  out  between  the  fingers  we 
stretch  it  to  ten  or  fifteen  times  its  original  length,  the 
appearance  of  the  fibre  changes  and  it  becomes  white. 
At  the  same  time  the  thread  becomes  quite  warm  and 
strongl}''  tends  to  contract,  in  such  manner  that  if  we 
release  one  of  its  extremities  it  immediately  returns  to 
its  original  length  and  falls  to  its  previous  temperature. 
Sensible  heat  has  disappeared  and  has  been  converted 
into  mechanical  work.  Indeed  if  we  plunge  the  stretched 
thread  into  water  and  thus  abstract  its  heat,  it  remains, 
so  to  speak,  fixed  in  its  extended  condition  and  does 
not  develop  any  mechanical  work. 


HEAT.  37 

"But  if  we  take  the  thread  elongated  in  this  manner, 
and  restore  its  heat  to  it,  it  contracts  with  a  considerable 
force. 

"  If  we  apply  a  weight  to  the  cooled  thread  the  latter 
has  no  tendency  to  raise  it  ;  but  if  we  seize  the  thread 
in  the  fingers  we  feel  it,  as  it  is  warmed  by  their  heat, 
swell  and  shorten,  raising  the  weight  ;  there  is  a  pro- 
duction of  mechanical  work. 

"If  we  warm  the  thread  in  this  way  in  several  places 
we  produce  a  series  of  swellings,  each  of  which  raises 
the  weight  for  a  certain  distance.  Finally,  if  we  heat  it 
throughout  its  length,  the  thread  returns  to  its  original 
dimensions,  except  for  the  slight  elongation  produced 
by  the  weight. 

"  There  are  close  analogies  between  these  phenomena 
and  those  observed  in  muscular  tissue.  These  analogies 
have  seemed  remarkable  to  me  ;  they  appear  to  indicate 
new  views  as  to  the  oriq-in  of  muscular  work."  * 

II. 

The  experiments  of  the  laboratory  do  not  always  lead 
to  conclusions  applicable  to  common  phenomena  ;  how- 
ever, everybody  must  have  noticed  the  influence  of  tem- 
perature on  bodily  movements. 

When  it  is  very  cold  and  the  hand  is  numb,  we  cannot 
make  use  of  its  muscles,  and  if  we  plunge  the  arm  in 
ice-cold  water  for  some  minutes,  there  ensues  a  tempo- 
rary paralysis  of  the  whole  limb. 

There  is  a  greater  aptitude  for  bodily  exercises  in 
summer  than  in  \\inter.  Professors  of  gymnastics,  who 
are  never  at  a  loss  for  an  explanation,  say  that  the  body 
is  more  siipple.  It  is  not  on  account  of  suppleness  that 
the  muscle  works  better  when  it  is  warm.  There  is  no 
suppleness  required  to  press  a  dynamometer  in  the 
hand  ;  but  we  note  a  great  difference  in  the  power  of 
the  grasp,  according  as  the  muscles  are  cooled  or  heated. 

Heat  causes  in  muscular  fibres  the  first  stage  of 
contraction,   or   at   least   an    aptitude  for  coming   into 

•  Marey.     La  Machine  Animale. 


38  PHYSIOLOGY  OF   BODILY  EXERCISE. 

action  more  quickly  under  the  influence  of  the  will.  A 
heated  muscle  seems  to  have  stored,  in  a  sense,  a  latent 
force.  It  has  been  ascertained  that  the  maximum  apti- 
tude for  contraction  is  exhibited  by  human  muscles  at 
about  40°  C.  It  follows  that  a  man  whose  muscles  are  at 
this  temperature,  is  able  to  act  more  quickly,  and  at 
once  can  make  use  of  all  his  force. 

A  bodily  exercise  is  performed  with  more  vigour 
and  ease  when  heat  has  raised  the  temperature  of  the 
muscles.  This  fact  is  so  well  known  that  there  are 
characteristic  phrases  to  express  it  in  common  speech. 
We  say  of  a  man  beginning  an  exercise  of  strength  or 
skill,  whose  movements  have  not  yet  acquired  all  their 
force  and  precision,  that  he  has  not  yet  wainned  to  his 
work. 

We  could  quote  a  number  of  examples  to  show  the 
necessity  of  preliminary  work  to  warm  the  muscles 
before  performing  an  exercise  requiring  a  great  expendi- 
ture of  force. 

It  is  interesting  to  see  that  nature  has  given  to 
animals  and  to  man  the  instinct  of  making  these  pre- 
paratory movements  when  there  is  a  question  of  attack 
or  defence. 

Anger  is,  in  principle,  the  prelude  to  an  attack  on  an 
enemy,  and  animals  or  men,  wishing  to  attack,  make  a 
series  of  gestures  which  are,  in  a  sense,  a  preparation  of 
their  means  of  action.  The  dog  draws  back  his  lips  to 
show  the  teeth  which  are  going  to  bite,  and  man  in- 
stinctively assumes  a  favourable  position  for  the  struggle. 
"  He  carries  his  head  erect,  with  his  chest  well  ex- 
panded, and  the  feet  planted  firmly  on  the  ground.  He 
holds  his  arms  in  various  positions,  with  one  or  both 
elbows  squared,  or  with  the  arms  rigidly  suspended  by 
his  sides.  With  Europeans  the  fists  are  commonly 
clenched."* 

According  to  our  idea,  the  evident  end  of  anger  is,  as 
Darwin  says,  to  prepare  a  man  or  an  animal  for  strife  ; 
but  the  preparation  does  not  only  consist  in  making  him 

*  Darwin.    The  Expression  of  the  Emotions,  p.  246. 


HEAT.  39 

take  a  favourable  attitude  for  the  strategy  of  attack  and 
defence,  the  preparation  above  all  is  by  causing  him  to 
make  movements  which  raise  the  temperature  of  the 
body.  It  has  al\va}'s  been  noticed  that  the  body  of  an 
angry  man  becomes  warm,  and  the  phrase  "  boiling  with 
rage"  has  passed  into  common  speech.  When  the  anger 
is  not  sufficiently  violent  spontaneously  to  warm  the 
muscles,  the  man  and  the  animal  make  instinctively  a 
series  of  movements  which,  while  threatening  the  ad- 
versary, tend  to  increase  the  vital  heat  and  to  raise  the 
body  to  the  degree  of  temperature  most  favourable  for 
action.  Everyone  has  noticed  that  the  gestures  are 
more  exuberant  the  less  decided  the  man  is  to  attack. 
If  the  anger  is  really  very  violent,  gestures  are  useless  ; 
the  man,  in  a  paroxysm  of  fury,  does  not  waste  his  time 
gesticulating,  but  throws  himself  at  once  on  his  enemy. 
His  muscles  have  acquired,  merely  by  the  acceleration 
of  the  blood-current,  the  temperature  necessary  for 
action. 

The  gestures  of  anger  are,  in  reality,  violent  move- 
ments which,  in  a  short  time,  raise  the  temperature  of 
the  bodv  to  the  degree  at  which  the  muscles  act  most 
vigorously.  These  gestures  occur  in  all  animals.  They 
cannot  be  satisfactorily  explained  w^ithout  admitting 
that  they  are  a  preparatory  work,  the  object  of  which  is 
to  give  the  animal  full  power  of  action.  The  lion  which 
lashes  its  sides  with  its  tail,  the  bull  tearing  the  ground 
.with  its  horns,  are  doing  the  same  thing  as  the  race- 
horse in  its  preliminary  canter.  When  a  horse  has  a 
little  gallop  some  minutes  before  the  race,  the  tempera- 
ture of  its  muscles  is  raised  a  degree  ;  we  are  heating  up 
a  locomotive. 

We  discover  this  preparatory  working  of  the  muscles 
in  all  exercises  needing  vigour  or  skill.  The  pianist  plays 
a  few  scales  or  a  short  prelude  before  attacking  his  great 
piece.  In  fencing,  we  make  preliminary  passes  before 
beginning  the  assault.  In  boxing,  which  needs  a  great 
expenditure  of  force  and  skill,  there  is  always  some 
preliminary  sparring.  The  object  of  all  these  move- 
ments is  to  raise  the  temperature  of  the  muscles  brought 


40  PHYSIOLOGY  OF   BODILY   EXERCISE. 

into  action.  A  muscle  which  has  been  at  work  is  a 
warm  muscle,  and  a  warm  muscle  is  already  in  the  first 
stage  of  contraction,  and  submits  more  easily  to  the 
action  of  the  will ,  as  the  speed  already  possessed  by  a 
moving  mass  renders  more  effective  a  fresh  impulse 
communicated  to  it. 

The  effort  of  a  horse  which  starts  a  motionle:s 
vehicle  is  always  more  severe  than  that  required  to 
change  its  pace  from  a  walk  to  a  trot.  The  warm 
muscle  is  already  in  a  state  of  semi-contraction,  and  the 
will  has  every  .facility  for  increasing  and  directing  its 
action. 

Many  phenomena  of  common  occurrences  are  ex- 
plained by  this  action  of  heat  upon  muscle.  We  know 
that  the  temperature  of  the  body  is  lowered  during 
sleep  ;  in  hibernating  animals  which  sleep  all  the  winter, 
the  temperature  falls  from  37°  C.  to  20°  C.  Muscular 
contractility  diminishes  in  the  same  proportion.  By 
means  of  registering  apparatus,  Marey  has  obtained 
graphic  tracings  showing  the  form  and  intensity  of  the 
muscular  contraction  in  the  marmot.  He  has  noted  a 
considerable  difference  between  the  moment  when  the 
animal  has  just  awakened,  and  when  it  is  fully  awake. 
The  temperature  and  the  muscular  energy  increase 
together. 

Everyone  can  notice  in  himself  a  certain  numbness 
of  the  muscles  on  getting  out  of  bed.  Animals  surprised 
in  their  sleep  do  not  at  once  recover  their  muscular 
energy,  and  have  not  at  first  the  swiftness  they  gain 
after  some  seconds'  flight.  When  a  hare  is  put  up  and 
has  two  shots  fired  at  it  which  do  not  touch  it,  the 
unskilful  sportsman  almost  always  thinks  it  is  wounded. 
It  seems  unable  to  run,  and  its  first  steps  are  so  slow 
that  a  dog  could  catch  it  ;  but  after  it  has  gone  a  few 
yards  the  illusions  of  the  inexperienced  shot  are  dis- 
pelled ;  the  animal  becomes  warm  and  goes  like  an 
arrow. 

Heat  is  then  an  indispensable  element  in  muscular 
contraction.  But  the  temperature  must  not  rise  too 
high,   for    then,    instead    of   increasing    the    activity   of 


HEAT.  41 

muscle,  heat  destroys  it.  In  man  and  the  mammah'a,  a 
muscle  becomes  incapable  of  contraction  at  45°  C.  At 
this  temperature  vital  combustions  affect  the  muscular 
tissues  too  profoundly,  and  destroy  their  properties  in  a 
definite  manner  :  the  muscle  dies. 

Excessive  muscular  work  can  raise  the  system  to  a 
temperature  at  which  the  body  can  no  longer  live. 
This  is  one  of  the  reasons  why  a  diHven  animal  dies. 
If  the  work  becomes  excessive,  so  much  heat  is  pro- 
duced that  radiation  from  the  surface  of  the  body  and 
evaporation  of  the  liquids  of  the  economy  no  longer 
suffice  to  keep  the  temperature  at  a  level  compatible 
with  life.  The  overheated  blood  poisons  the  nerve- 
centres  ;  the  animal  whose  body  is  surcharged  with  heat 
owing  to  too  prolonged  exercise,  dies  in  a  condition 
similar  to  that  of  a  man  with  sunstroke  under  a  tro- 
pical sun. 


CHAPTER  ÎV. 

COMBUSTION. 

General  Idea  of  Combustion — Chemical  Sources  of  Heat- 
Ancient  and  Modem  Theories — Part  played  by  Oxygen— Oxi- 
dation ;  Hydration  ;  Decomposition— Complexity  of  the  Chemical 
Phenomena  which  Produce  Heat — Combustible  Materials  ; 
Food-Stuffs  ;  Reserve- Materials  ;  Tissue-Materials — Results 
of  Combustion — Products  of  Dissimilation — Products  of  In- 
completed Oxidation  ;  Uric  Acid — Elimination  of  Products  of 
Dissimilation  —  Eliminating  Organs  —  Auto- Intoxication  — 
Dangers  of  Human  Miasma. 

I. 

Work  and  heat  do  not  exist  independently  in  the 
animal  machine.  Now  work  goes  on  incessantly  in  us. 
During  repose,  and  even  during  sleep,  the  internal  organs 
are  never  inactive.  The  heart  beats  and  expends  con- 
siderable force  in  propelling  the  blood  through  the 
vessels  ;  the  chest  rises  and  falls  in  respiration  ;  the 
stomach  and  intestines  perform  peristaltic  movements  to 
pass  the  food-stuffs  onwards. 

The  work  of  the  human  body  continues  then  night 
and  day  ;  it  only  ceases  with  death,  and  at  this  moment 
also  is  extinguished  the  fire  of  animal  heat. 

Life  is  impossible  without  heat. 

The  heat  from  which  the  human  machine  draws  the 
force  necessary  for  its  existence  is  derived  from  combus- 
tion which  goes  on  inside  the  organism.  In  chemistry, 
the  term  combustion  is  applied  to  the  combination  of 
two  or  more  bodies  with  each  other,  accompanied  by 
the  production  of  light  and  heat. 

It  is  evidently  a  considerable  extension  of  the  meaning 


COMBUSTION.  43 

of  the  word  combustion,  and  a  somewhat  figurative  use, 
to  apply  it  to  the  phenomena  which  cause  the  heating 
of  the  body  during  work.  The  chemical  combination 
going  on  in  us  is  not  accompanied  by  the  production  of 
light.  The  phenomena  which  produce  vital  heat  re- 
semble fermentation  rather  than  combustion  properly 
so  called.  For  example,  they  rather  resemble  the 
changes  which  go  on  in  a  damp  hay-stack,  than  the 
phenomena  we  observe  in  a  burning  fire. 

The  sources  of  vital  heat  are  chemical  combinations 
of  infinite  variety. 

It  has  been  long  considered  that  all  the  combustions 
in  the  system  are  due  to  the  action  of  oxygen  upon  the 
living  tissue.  At  the  present  time  we  fully  admit  the 
capital  importance  of  oxygen  in  the  chemical  combina- 
tions which  are  the  source  of  work  ;  but  we  recognize  that 
other  bodies  take  a  certain  share  in  the  vital  actions 
capable  of  producing  heat  ;  hydrogen  for  instance. 

Further,  many  chemical  reactions  which  produce 
heat  are  accomplished  by  the  simple  splitting  up  of  a 
substance  into  two  others  which  entered  into  its  compo- 
sition. In  other  cases  the  combination  is  limited  to  the 
hydration  of  a  substance  which  absorbs  some  molecules 
of  water,  or  to  its  dehydration  by  loss  of  these  molecules.* 

The  problem  of  vital  combustion  has  then  become 
very  complicated  of  late  ;  we  may  say  that  it  is  some- 
what perplexed,  and  that  it  is  difficult  to  give  in  a  few 
words  a  clear  and  concise  summary  of  it.  It  is  a 
chapter  of  physiology  which  is  being  re-written,  and  we 
cannot  at  this  moment  formulate  our  conclusions. 

All  that  we  are  able  to  say  is,  that  the  unceasing 
work  of  the  internal  organs,  which  constitutes  life,  is  the 
transformation  of  one  force,  heat.  This  force  is  itself 
derived  from  the  chemical  reactions  which  set  free  the 
heat  contained  in  a  latent  condition  in  the  molecules 
of  which  the  organs  of  the  body  are  made  up,  and  in 
the  foods  which  serve  to  nourish  the  organs. 

The   chemical  reactions   which   set   free   and  render 

^  Lambling.     Sources  of  Heat  and  Force. 


44  PHYSIOLOGY  OF   BODILY  EXERCISE. 

sensible  by  the  thermometer  the  latent  heat-energy,  con- 
sist in  the  expenditure  of  two  classes  of  substances  : 
the  alimentary  substances  introduced  into  the  blood  by 
digestion,  and  the  organic  substances  which  form  part 
of  our  bodies,  and  which  are  removed  to  give  place  to 
new  substances  obtained  from  the  food. 

Certain  products  of  digestion  which  have  only  just 
entered  the  blood  are  made  use  of  to  undergo  the 
chemical  combinations  which  produce  heat,  and  after 
their  chemical  constitution  has  been  changed  by  this 
combustion,  they  are  expelled  from  the  body  without 
ever  having,  in  a  stable  manner,  become  part  of  our 
system.  They  only  pass  through  the  system,  being 
changed  in  the  process. 

On  the  day  following  too  hearty  a  meal,  there  may 
be  seen  at  the  bottom  of  the  chamber-pot,  a  yellowish 
white,  or  a  brick-red  deposit.  This  is  made  up  of  very 
different  chemical  substances,  certainly,  from  those 
which  were  absorbed  the  night  before,  but  it  results 
from  the  transformation  of  the  alimentary  substances 
into  new  products  which  have  been  rejected  from  the 
system  because  they  were  present  in  excess,  and  the 
organs  of  the  body  could  make  no  profitable  use  of 
them.  Here  we  have  a  case  in  which  the  food-stuffs 
have  furnished  the  elements  for  vital  combustions. 

lo  other  circumstances,  however,  the  combustions 
take  place  at  the  expense  of  elements  which  form  an 
integral  part  of  the  body.  A  man  who  performs  violent 
muscular  work  after  a  two  days'  fast,  cannot  furnish  the 
quantity  of  heat  needed  by  this  work,  from  the  products 
of  digestion.  But  the  urine  of  this  man,  when  the  work 
is  over,  will  deposit  a  sediment  similar  in  appearance 
and  constitution  to  that  from  the  urine  of  the  man  who 
has  dined  too  freely.  In  this  case  the  chemical  com- 
binations, which  have  given  rise  to  the  heat,  and  at  the 
same  time  to  the  product  deposited  by  the  urine,  have 
not  been  made  at  the  expense  of  substances  introduced 
into  the  system  from  without,  but  at  the  expense  of  the 
organism  itself,  and  of  the  tissues  which  form  it. 

Since  the  system   is   entirely  built  up  by    materials 


COMBUSTIvON.  45 

drawn  from  the  daily  food,  it  is  not  surprising  that  there 
arc  in  it  substances  analop^ous  in  chemical  composition 
to  those  in  the  food,  and  that  the  elements  of  the  body 
can  supplement,  in  case  of  fast,  the  elements  usually 
supplied  by  the  food. 

Hence  the  chemical  sources  of  heat,  and  consequently 
the  forces  from  which  work  proceeds,  may  arise  either 
from  the  food,  or  from  the  molecules  composing  the  body. 

The  animal  machine  is  so  constructed  as  to  be  able 
to  perform  its  functions  for  a  long  period  without  ex- 
ternal assistance.  We  see  the  proof  of  this  every  day,  in 
the  diseases  which  keep  the  patient  on  a  very  restricted 
diet  for  some  weeks.  We  have  recently  had  a  striking 
demonstration  from  the  experiments  to  which  two 
eccentric  individuals  *  submitted  themselves,  one  of 
whom  was  able  to  abstain  from  food  for  50  days,  and  in 
spite  of  this  to  perform  bodily  exercise. 

The  body  is  then  able  to  furnish  the  elements  of  the 
chemical  combinations  which  produce  heat  and  muscular 
work  without  the  aid  of  food.  But  if  these  elements 
were  furnished  at  the  expense  of  organs  which  are  the 
essential  parts  of  the  machinery  we  can  understand  that 
the  latter  would  very  quickly  deteriorate  and  be  worn 
out.  There  must  then  be  in  the  body  materials  which 
act  as  a  go-between  for  the  food  and  the  organs.  These 
materials,  known  as  reserves^  are  substances,  the  dis- 
similation of  which  cannot  compromise  the  regular 
performance  of  the  organic  functions.  The  reserve 
materials  are  the  result  of  a  kind  of  tribute  levied 
every  day  on  the  food,  and  stored  up  in  various  parts  of 
the  body  as  in  a  savings-bank,  on  which  the  system  can 
draw  when  it  has  need. 

The  reserve  materials  are  constituted  anatomically  for 
the  most  part  of  fat  ;  but  fat  is  not  the  only  tissue  of 
the  body  used  for  combustion.  There  are  other  sub- 
stances, for  instance  a  variety  of  sugar  known  as  iiiosit, 
which  is  found  in  great  abundance  in  muscular  tissue, 
and  the  combustion  of  which  is  one  of  the  sources  of 

*  Sued  and  MerJatti. 


46  PHYSIOLOGY   OF   BODILY   EXERCISE. 

the  heat  of  work.  There  are  undoubtedly,  in  muscular 
tissue,  nitrogenous  products  which  play  the  part  of 
reserve  materials,  for,  according  to  our  own  observations 
which  are  recorded  in  the  second  part  of  this  book, 
persons  who  ordinarily  do  little  work,  and  who  in 
consequence  are  provided  with  an  abundance  of  reserve 
materials,  show  in  their  urines  after  unusual  exertion,  a 
great  quantity  of  nitrogenous  excretion.  Their  urine  is 
similar  to  that  of  persons  whose  diet  is  too  rich  in  flesh 
and  consequently  in  proteids. 

But  food  and  the  reserve  materials  are  not  the  only 
elements  furnished  to  the  chemical  combinations  which 
we  call  combustion.  In  certain  caseâ,  food  being  cut 
off,  and  the  reserve  materials  being  exhausted,  vital  heat 
is  maintained  and  life  persists.  Still  more  even,  violent 
muscular  work  may  be  done  in  such  conditions,  and 
consequently  intense  combustions  be  carried  on.  These 
combustions  are  then  made  at  the  expense  of  the 
essential  tissues  of  life,  of  those  which  compose  the 
intimate  woof  of  the  organs.  In  these  cases  the 
machine  still  performs  its  functions,  but  it  is  at  the 
expense  of  the  essential  elements  of  its  composition.  It 
uses  itself  up. 

Such  are,  from  the  physiological  point  of  view,  the 
three  sources  from  which  the  vital  work  of  the  internal 
organs  and  the  muscular  work  of  external  life,  which  is 
but  the  exaggeration  of  the  other,  draw  the  elements  of 
which  the  chemical  combinations  give  rise  to  the  ex- 
penditure of  heat. 

II. 

From  the  chemical  stand-point,  what  are  the 
substances  used  in  these  combustions  ?  This  is  a 
question  which  in  a  few  years  has  been  answered  in 
several  different  ways  and  to  which  a  satisfactory  and 
definite  answer  has  not  yet  been  given. 

It  would  be  uninteresting  to  follow  in  all  its  successive 
developments  the  theory  of  vital  combustions,  and  it 
will  be  better  for  us  to  give  a  summary  of  the  actual 
state  of  the  science. 


COMBUSTION".  4> 

It  îs  admitted  by  the  most  recent  writers  on  the 
question,  that  the  combustion  of  non-nitrogenous  sub- 
stances, such  as  fats  and  sugars,  is  the  almost  exclusive 
source  of  muscular  work.  The  theory  is  now  in  great 
disfavour  that  the  muscle  burns  up  its  own  substance  in 
contracting  to  perform  work,  and  liberates  a  great 
quantity  of  nitrogenous  products.  Liebig's  experiments 
showed  an  increase  in  the  elimination  of  urea  after 
^vork  ;  more  recent  observations  have  seemed  to  upset 
those  of  Liebig,  and  it  is  believed  that  the  elimination  of 
urea  is  not  increased,  and  may  even  be  diminished  by 
muscular  work.  It  cannot,  however,  be  denied  that  a 
part  of  the  expense  of  the  combustions  of  work  falls  on 
the  muscle  itself,  for  its  chemical  composition  is  pro- 
foundly modified  by  muscular  work  ;  but  the  modifica- 
tion is  attributed  to  changes  of  the  non-nitrogenous 
substances  which  enter  into  the  composition  of  the 
muscle-plasma,  to  glycogen,  for  instance. 

Glycogen  is  a  hydrocarbon  which  can  be  transformed 
into  sugar,  and  can  play  a  similar  part  in  the  chemical 
actions  of  work  to  starches  and  fats.  But  we  must 
allow  that  in  certain  cases  the  nitrogenous  substances  of 
muscle  are  made  use  of  for  the  combustions  of  work. 
The  proofs  of  this  are  as  follows,  The  first  is  that 
muscle  diminishes  in  size  in  certain  forms  of  muscular 
exhaustion,  which  Ave  shall  study  later  on  in  the  chapter 
on  Fatigue.  The  other,  which  is  more  direct,  is  drawn 
from  our  own  observations  on  the  composition  of  urines 
after  work,  which  show  in  an  irrefutable  manner  an 
increase  in  the  elimination  of  uric  acid  after  muscular 
exercise.  We  must  then  admit  that  the  nitrogenous  as 
well  as  the  non-nitrogenous  tissues  can  be  made  use  of 
in  the  combustions  of  work.  And  we  shall  show  in  the 
chapter  on  Stiffness,  that  the  reserve  materials  destined 
for  the  supply  of  these  combustions  are  not  only  fats, 
but  must  of  necessity  also  be  nitrogenous  substances, 
because  the  nitrogenous  waste-products  in  urine  are 
especially  abundant  in  individuals  who  are  not  accus- 
tomed to  use  their  muscles,  and  who  consequently  have 
not  used  up  their  reserve  materials. 


48  PHYSIOLOGY  OF   HODILY  EXERCÎS2. 

Thus,  the  heat  needed  for  work  results  from  chemical 
changes  which  are  accompanied  by  the  evolution  of 
heat,  and  which  are  undergone  by  certain  nitrogenous 
or  non-nitrogenous  elements  forming  an  integral  part  of 
the  system  or  introduced  as  food.  These  chemical  com- 
binations are  mostly,  but  not  exclusively,  oxidations^ 
that  is,  combinations  with  oxygen.  The  oxygen  is 
introduced  into  the  system  by  respiration.  It  is  fixed 
and  retained  there  so  as  to  form  a  provision  which  will 
be  always  ready  for  the  chemical  combinations  which 
are  rendered  necessary  by  the  different  functions  of  life. 
Although  oxidations  are  not  the  only  chemical  actions 
of  work,  they  are  the  chief  ones,  and  oxygen  is  almost 
always  made  use  of  in  the  chemical  combinations  which 
produce  heat. 

The  oxidised  compounds  formed  during  combustion, 
can  be  placed  in  two  categories  :  the  products  of 
complete  and  of  incomplete  oxidation.  Carbonic  acid 
and  water  are  the  final  stages  of  all  the  complete 
oxidations  of  hydrocarbon  substances,  and  urea  is  the 
last  stage  of  complete  oxidation  of  nitrogenous 
substances. 

Besides  these  substances  there  are  other  products 
formed  at  the  expense  of  the  same  tissues  with  which  a 
smaller  quantity  of  oxygen  is  combined,  and  which  are 
consequently  the  result  of  a  less  advanced  oxidation  or 
of  an  incomplete  combustion. 

In  a  furnace,  the  oxygen  of  the  air,  which  combines 
with  the  blocks  of  wood  in  order  to  burn  them,  gives 
rise  to  products  of  incomplete  combustion  which  are 
smoke  and  soot.  These  products  have  not  been  carried 
to  the  furthest  stage  of  oxidation  or  combustion,  for  we 
can  submit  them  afresh  to  the  action  of  the  oxygen  of 
the  airi  n  smoke-consuming  apparatus  in  order  to  burn 
them  more  completely. 

Similarly  uric  acid,  for  example,  is  a  product  of 
incomplete  combustion,  and  can  undergo  a  further 
degree  of  oxidation.  If  we  inject  a  quantity  of  this 
substance  into  the  blood  of  a  living  animal  it  is  further 
oxidised  and  transformed  into  urea. 


COMBUSTION.  49 

Uric  acid  is  only  one  of  the  numerous  organic  pro- 
ducts which  result  from  incomplete  oxidation,  and  which 
we  call  waste-products  of  combustion. 

The  combustions  do  not  cause  the  complete  disappear 
ance  of  the  tissues  on  which  they  feed  ;  they  change  them 
as  does  the  flame  of  a  fire  the  coal  and  wood  it  consumes. 
The  burning  wood  gives  rise  to  products  of  decomposi- 
tion, the  cinders  and  soot  which  are  found  in  a  burnt-out 
fire-place.  Similarly  the  system  after  work  contains  thî 
products  of  combustion — or  as  they  have  also  been  called, 
products  of  dissimilation,  because  they  are  no  longer 
similar  to  the  organic  tissues  of  which  they  at  one  time 
formed  a  part. 

III. 

The  products  of  dissimilation,  the  history  of  which  is 
still  sufficiently  obscure,  have  one  character  in  common, 
they  are  all  injurious  to  life,  and  are  rejected  from  the 
body  as  soon  as  they  are  formed,  just  as  the  cinders  and 
smoke  are  removed  from  the  fire. 

These  waste-products  are  dangerous  to  the  system, 
and  their  presence  in  the  blood  becomes  incompatible 
with  health  when  there  is  any  excess  of  them.  There  is 
no  danger  when  there  is  only  a  moderate  quantity,  for 
then  the  system  can  quickly  relieve  itself  of  them  by 
means  of  the  organs  specially  charged  with  their  elimi- 
nation. 

The  lungs,  the  kidneys,  the  skin,  and  the  intestine  have 
among  their  functions  that  of  eliminating  from  the  blood 
whatever  harmful  or  useless  substances  are  present  in  it, 
whether  they  have  been  formed  there  or  introduced  into 
the  blood  from  without. 

These  four  organs  are  specially  charged  with  the  re- 
moval from  the  system  of  products  which  are  formed 
everywhere  as  a  result  of  combustions.  The  lungs  re- 
move carbonic  acid,  the  kidneys  urea,  the  skin  lactic  acid, 
etc.  All  these  are  the  waste  products  of  vital  combus- 
tions. To  these  three  well-known  substances  it  is  neces- 
sary to  add  a  great  many  more,  of  which  we  know  very 
little.     Fresh  researches  are  daily  throwing  new  light  on 


50  PHYSIOLOGY  OF   BODILY  EXERCISE. 

the  functions  of  excretion,  and  show  the  capital  import- 
ance of  the  part  they  play  in  the  system. 

It  is  no  part  of  the  purpose  of  this  book  to  make  a 
complete  study  of  the  products  of  excretion,  but  it  is  in- 
dispensable for  the  exposition  of  our  views  on  the  results 
of  work  and  of  fatigue  to  insist  on  one  point  in  their  his- 
tory, on  the  dangers  to  which  the  system  is  exposed 
when  they  are  accidentally  retained  in  the  blood,  or 
when  their  elimination  is  incomplete. 

Long  before  chemical  analysis  had  proved  the  exist- 
ence of  poisonous  principles  in  the  waste-products  of  dis- 
similation, many  clinical  facts  had  indicated  that  these 
principles  must  exist.  We  have  long  known  that  the 
slightest  hitch  in  the  functions  of  an  excretory  organ 
immediately  produces  a  series  of  accidents  due  to  the 
retention  in  the  blood  of  the  waste-products  which  this 
organ  ought  to  eliminate. 

The  function,  the  suspension  of  which  causes  the  most 
grave  and  immediate  danger,  is  that  of  respiration. 
Should  the  lung  become  functionless  for  a  few  minutes, 
death  occurs  from  asphyxia,  which  is  a  poisoning  of  the 
blood  by  carbonic  acid.  Carbonic  acid  is  the  best  known 
and  the  most  abundant  of  the  products  of  combustion  : 
It  results  from  the  combustion  of  the  carbon  contained 
in  all  the  living  tissues.  The  formation  of  this  gas  in 
the  blood  is  continuous,  and  the  system  always  contains 
large  quantities  of  it,  but  the  quantity  compatible  with 
life  is  never  exceeded,  because  the  lungs  eliminate  the 
surplus  as  fast  as  it  is  formed.  If  the  respiratory  func- 
tion is  suspended,  the  poisonous  gas  accumulates  quickly 
to  an  extent  incompatible  with  life. 

Carbonic  acid  is  not  the  only  poisonous  product  elimi- 
nated by  the  respiratory  apparatus.  The  air  which  is 
driven  from  the  lung  in  expiration  is  saturated  with 
aqueous  vapour,  and  this  vapour  carries  with  it  a  product 
which  has  not  been  isolated,  and  which  is  formed  in  very 
small  quantity,  but  it  reveals  itself  by  its  unpleasant 
qualities  and  its  pestilential  smell.  This  product  has 
been  called  miasma.  If  we  go  in  the  morning  into  a 
dormitory  in  which  many  persons  have  passed  the  night, 


COMBUSTION.  51 

we  are  struck  by  an  unbearably  fetid  smell,  which  re- 
sembles no  other.  It  is  the  smell  of  the  miasma  exhaled 
from  the  lungs  of  the  persons  who  have  slept  there. 
The  air  is  vitiated  by  it. 

The  skin  eliminates  the  sweat,  which  contains  99  per 
cent,  of  water,  holding  in  solution  salts,  chlorides,  acids, 
such  as  lactic  acid  and  a  special  nitrogenous  acid  called 
Sîidoric  acid.     Urea  has  also  been  found  in  it. 

Besides  the  liquid  part  of  the  cutaneous  excretion, 
there  is  a  gaseous  part,  which  is  no  less  important. 
Various  volatile  acids  and  a  considerable  quantity  of 
carbonic  acid  are  exhaled  by  the  skin.  But  the  pro- 
ducts of  cutaneous  excretion  which  interest  us  most, 
those  which  best  establish  the  poisonous  power  of  the 
waste-products  of  nutrition,  are  at  present  little  known 
from  the  stand-point  of  chemical  analysis,  and  only 
manifest  their  existence  by  the  effect  produced  on  the 
system  when  their  elimination  is  prevented.  Their 
poisonous  properties  are  shown  by  the  following  experi- 
ment : — 

Take  a  large  dog,  shave  off  all  its  hair,  and  cover  its 
skin  with  a  coat  of  impermeable  varnish  or  with  collo- 
dion, in  such  a  manner  that  no  liquid  or  gaseous  product 
can  be  thrown  off  from  the  animal's  skin.  In  this  man- 
ner we  imprison  in  the  system  of  the  dog  all  the  products 
which  are  usually  eliminated  by  the  skin.  At  the  end  ot 
eight  hours,  on  an  average,  the  animal  dies. 

Sokolow,  the  Russian  physiologist,  who  performed 
the  experiment  we  have  quoted,  attributes  the  death  of 
the  varnished  animal  to  poisoning  by  the  principles 
which  are  no  longer  eliminated. 

The  kidneys  eliminate  a  great  quantity  of  the  pro- 
ducts of  organic  decomposition.  It  would  take  too 
long  to  enumerate  them  all.  The  chief  are  the  residues 
of  the  combustion  of  nitrogenous  substances  :  urea,  uric 
acid,  and  its  salts,  the  urates.  But  urine,  like  all  ex- 
cretions, contains  also  a  great  number  of  unknown  pro- 
ducts. In  any  case  no  one  will  dispute  the  import- 
ance of  a  rapid  removal  of  the  products  which  are 
carried  away  by  the  urinary  secretion. 


52  PHYSIOLOGY  OF   BODILY   EXERCISE. 

When  the  functions  of  the  kidney  are  abolished  by 
disease  altering  the  structure  of  that  organ,  urine  has 
no  longer  the  same  chemical  composition,  and  in  the 
end  does  not  carry  off  the  substances  which  are  usually 
eliminated  in  it.  Their  composition  is  changed  and  sim- 
plified ;  they  contain,  so  to  speak,  little  but  water.  Urea 
and  the  other  waste-products  of  vital  combustions,  being 
no  longer  eliminated  in  the  ordinary  manner,  accumulate 
in  the  blood,  and  can  be  detected  there  by  chemical 
analysis.  Urinary  poisoning,  or  uraemia,  soon  follows, 
and  quickly  ends  in  death. 

The  remarkable  experiments  of  Bouchard  have  estab- 
lished the  poisonous  properties  of  urine,  and  have  shown 
that  the  injection  of  this  liquid  into  the  veins  of  a 
healthy  animal  can  cause  its  death  in  a  short  time.* 

The  intestine  is  one  of  the  eliminating  organs  which 
must  reject  the  largest  quantity  of  the  waste-products  of 
combustion.  But  being  already  mixed  with  a  large 
quantity  of  food-residues,  and  also  receiving  the  secre- 
tions of  the  liver,  the  pancreas,  and  many  other  glands, 
it  is  very  difficult  to  discover  in  this  mixture  how  much 
is  derived  from  the  products  of  dissimilation.  A  simple 
observation  shows  that  the  intestine  receives  its  share  of 
the  eliminated  waste-products  of  combustion.  When 
there  is  increased  combustion  on  account  of  excessive 
muscular  activity,  there  are  always  more  evacuations, 
and  the  stools  are  more  liquid.  The  intestine  seems  to 
have  been  submitted  to  the  action  of  certain  laxative 
materials,  and  these  materials,  since  they  are  not  derived 
from  any  change  of  diet,  can  only  come  from  the 
organism  itself.  The  products  of  dissimilation,  in- 
creased in  quantity  by  exercise,  are  eliminated  by  the 
intestine,  and  stimulate  its  contraction,  causing  more 
frequent  stools. 

The  functions  of  the  intestine,  like  those  of  the  lungs, 
the  kidneys,  and  the  skin,  cannot  be  abolished  without 
{^rave  consequences.  When  the  faecal  matters  remain 
too  long  in  the  alimentary  canal,  owing  to  an  obstructive 

*  Bouchard^  les  Auto-intoxications. 


COMBUSTION.  53 

lesion,  there  ensues  a  series  of  accidents  which  may  be 
called  stercoral  poisoning,  and  which  are  due  as  nauch 
to  the  reabsorption  of  the  products  of  dissimilation,  as  to 
the  putrid  emanations  from  the  alimentary  residue. 

The  four  organs,  the  excretory  functions  of  which  we 
have  shortly  studied,  are  not  the  only  ones  charged 
with  the  elimination  of  products  of  which  the  body 
desires  to  rid  itself.  All  the  glands  can,  at  a  given  time, 
participate  in  this  function,  which  might  be  called  the 
cleansing  of  the  body.  The  presence  of  poisonous  sub- 
stances in  certain  secretions  has  been  discovered  by 
accident.  By  injecting  into  the  carotid  artery  of  a 
small  animal  the  saliva  of  a  fasting  man,  grave  conse- 
quences have  sometimes  been  produced.  This  shows 
that  the  saliva,  like  the  urine,  can  assist  in  the  elimina- 
tion of  products  of  dissassimilation  which  have  been 
demonstrated  to  be  poisonous. 

If  we  seek  to  summarise  the  conclusions  drawn  from 
the  facts  studied  in  this  chapter,  we  can  say  that  the 
work  of  the  muscles,  like  that  of  the  other  organs,  is 
accompanied  by  the  production  of  heat,  which  results 
from  chemical  actions  which  we  may  compare  with  com- 
bustions. The  living  tissues,  at  the  expense  of  which 
these  combustions  have  occurred,  have  changed  in  their 
chemical  composition,  and  become  noxious  to  life,  and 
must  be  rejected  from  the  body  under  diverse  forms  and 
by  special  organs. 

But  the  products  of  combustion  are  not  injurious  only 
to  the  organism  in  w^hich  they  are  accidentally  retained. 
If  absorbed  by  other  individuals,  they  can  produce  in 
them  the  same  bad  effects. 

We  said  a  few  words  about  the  miasma  exhaled  by 
the  lungs  and  the  skin.  These  products  are  present  in 
almost  infinitesimal  quantity,  but  possess  most,  power- 
fully poisonous  properties.  If  several  persons  are 
together  in  a  confined  place,  the  air  of  the  place  is 
quickly  infected  ;  but  the  disagreeable  odour  is  not  all  ; 
the  air  is  vitiated  and  dangerous  to  breathe.  Hence 
the  evil  results  of  deficient  ventilation. 


54  PHYSIOLOGY  OF   BODILY  EXERCISE. 

We  could  quote  numerous  facts  showing  the  serious 
nature  of  the  accidents  resulting  from  the  absorption  of 
this  product,  the  exact  nature  of  which  is  unknown,  but 
which  is  extremely  poisonous — the  human  miasma. 

Very  serious  symptoms,  and  even  fatal  results  have 
often  been  observed  in  persons  who  have  spent  a  long 
time  in  a  confined  space.  These  effects  of  "  stuffy  air  " 
are  not  due  to  asphyxia,  but  to  a  direct  poisoning  by 
the  human  miasma. 

Brown-Sequard  and  D'Arsonval,  in  a  communication 
made  to  the  Academy  of  Sciences,  on  January  i6ch, 
1888,  showed  that  human  breath  contains  a  most  active 
poison,  an  alkaloid  capable  of  killing  in  two  hours  an 
animal  into  which  it  is  injected. 


PART    TI. 
FAT  I  G  U  E. 

MUSCULAR       FATIGUE  —  BREATHLESSNESS  STIFF- 
NESS    OVERWORK EXHAUSTION THEORY      OF 

FATIGUE — REST. 


CHAPTER  r. 

LOCAL   FATIGUE. 

Experimental  Fatigue — Absolute  and  Relative  Fatigue— Fatigue 
in  Ordinaiy  Conditions  of  Work  ;  it  is  always  Relative — Ex- 
amples of  Relative  and  of  Absolute  Fatigue — Causes  of 
Sensation  of  Fatigue — Causes  of  Muscular  Powerlessness — 
Influence  of  Wabte-Products  of  Combustion  ;  Transmission 
of  Fatigue  to  Muscles  which  have  not  been  Working — Use  of 
Fatigue — Part  played  by  the  Brain  in  Fatigue.  Unconscious 
Movements  cause  less  Fatigue  than  Voluntary  Movements  ; 
Practical  consequences. 

I. 

If  we  isolate  one  of  the  muscles  of  a  living  animal  and 
pass  an  electric  current  through  it,  we  see  that  it  con- 
tracts as  long  as  the  passage  of  the  current  lasts.  But 
if  the  experiment  is  prolonged,  the  muscle  after  a  time 
contracts  more  feebly  ;  a  little  later  there  comes  a  stage 
when  the  muscle  does  not  contract  at  all  :  it  is  fatigued. 

Fatigue  is  at  first  only  relative,  and  the  muscle  will 
contract  afresh  if  stimulated  by  a  current  stronger  than 
the  first.  But  there  comes  a  time  when  fatigue  is  abso- 
lute, that  is  to  say  the  muscle  has  lost  the  property  of 
contracting  under  the  influence  of  the  most  powerful 
electric  stimuli. 

A  human  muscle  never  reaches,  in  consequence  of  work, 
the  condition  of  absolute  fatigue,  of  complete  powerless- 
ness, which  we  observe  in  animals  under  experiment. 
What  prevents  this  is  the  painful  sensation  experienced 
by  the  man  before  the  time  when  the  muscle  becomes 
absolutely  incapable  of  action.  Under  the  influence  of 
the  suffering  which  the  contraction  causes,  the  work  is 


58      '  PHYSIOLOGY  OF  BODILY  EXERCISE. 

stopped  and  the  muscle  rests.  Here  is  the  capital  dif- 
ference between  true  absolute  fatigue,  such  as  can  be 
produced  by  experiment  on  animals,  and  the  fatigue 
observed  clinically  in  a  man  at  work. 

That  which  dominates  in  the  fatigue  of  a  man  per- 
forming any  exercise  is  the  subjective  element,  the 
painful  sensation  which  prevents  him  from  continuing 
his  work  until  the  muscle  becomes  absolutely  exhausted. 
We  can  represent  the  effort  made  by  a  powerful  man 
to  carry  his  exercise  to  the  last  possible  limits,  as  a 
combat  between  the  will  which  commands  and  the  sen- 
sibility which  rebels. 

The  most  energetic  will  is  unable  to  use  up  the 
contractile  power  of  a  muscle  as  completely  as  do 
mechanical  or  physical  agents.  When  a  fatigued  man 
ceases  the  effort  which  he  has  long  been  making,  we 
say  that  his  muscles  are  exhausted  :  this  is  not  yet  so. 
The  proof  of  this  is  as  follows  : — 

We  know  that  one  of  the  most  tiring  attitudes  to 
assume  is  that  which  consists  in  holding  the  arm 
horizontally  outstretched.  The  deltoid  muscle  in  this 
case  does  most  of  the  work.  There  are  few  men  vigorous 
enough  to  be  able  to  hold  out  an  arm  in  this  manner 
for  more  than  five  or  six  minutes.  At  the  end  of  this 
time  the  deltoid  can  act  no  longer  and  the  arm  drops. 
But  the  muscle  is  not  exhausted  :  its  fibres  still  possess 
a  great  contractile  force,  and  this  is  proved  by  the  fact 
that  certain  agents,  such  as  electricity,  can  bring  into 
play  this  motor  force  over  which  the  will  has  no  longer 
any  action.  If,  in  a  man  who  has  been  holding  his  arm 
outstretched,  we  wait  till  the  sensation  of  fatigue 
becomes  intolerable,  and  if,  at  the  moment  when  the 
man  declares  he  has  used  up  all  his  power,  and  is  about 
to  let  his  arm  fall,  we  apply  a  strong  electric  stimulus  to 
the  deltoid  muscle,  the  fatigue  seems  to  vanish,  and  the 
arm  remains  outstretched  ;  the  muscle  had  not  yet  lost 
its  contractile  power. 

What  is  the  cause  of  this  local  fatigue  ?  A  double 
answer  is  needed  to  this  question  ;  we  must  say  why 
the  work  renders  muscular  contraction  painful  in  a  tired 


LOCAL  FATIGUE  59 

limb,  and  why  also  the  muscle  which  has  been  long  at 
work  finally  loses  for  a  time  the  power  of  contraction. 

Often  repeated  muscular  contraction  becomes  painful 
mechanically,  owing  to  the  repeated  shocks  and  dis- 
turbances occasioned  in  the  muscle  itself  and  in  the 
neighbouring  tissues.  Every  mechanical  action  sub- 
mitting the  muscular  masses  of  the  body  to  compressions, 
movements  and  shocks  similar  to  those  produced  by 
work  can  bring  about,  just  like  work,  a  sensation  of 
fatigue.  What  we  call  "  massage  "  is  a  series  of 
manipulations  to  which  muscles  are  submitted.  After 
the  action  exercised  on  the  muscles  by  the  hand  of  the 
masseur,  sensations  of  local  fatigue  are  experienced, 
similar  to  those  produced  by  muscular  work.  We  must 
then  conclude  that  the  sensation  of  pain  in  a  region 
which  has  worked,  is  due  to  the  same  cause  as  that  in  a 
region  which  has  undergone  massage,  that  is  to  a 
mechanical  action. 

And  this  action  is  easily  explained.  The  muscle  is 
traversed  by  a  number  of  sensory  nerve-filaments.  These 
little  twigs  are  rubbed  and  twisted  by  the  movement  of 
the  muscular  fibres  which  swell  and  harden  during  the 
energetic  contraction  of  work.  The  muscular  fibres  are 
themselves  pulled  about,  and  the  tendons,  the  aponeur- 
oses of  insertion,  and  the  synovial  membranes  undergo 
repeated  friction.  There  results,  then,  from  very  violent 
muscular  work  a  genuine  traumatism  in  the  whole  region 
which  is  the  seat  of  the  work,  and  the  consequences  of 
this  traumatism  may  be  the  same  as  those  due  to 
external  causes,  as  for  instance,  contusions.  Frequently, 
as  we  shall  see  in  speaking  of  the  accidents  of  work^ 
ruptures,  inflammations,  and  even  abscesses  may  result 
from  excessive  work.     . 

But  apart  from  these  causes  of  discomfort,  the  muscle 
at  work  undergoes  others  less  known  and  more  interest- 
ing. In  the  muscular  fibre,  modifications  of  nutrition 
take  place,  due  to  the  combustions  accompanying 
contraction.  Every  muscle  in  contracting  becomes 
heated,  and  this  increase  of  temperature  is  due  to  the 
chemical  combinations  of  which  we  have  spoken  in  the 


6o  PPIYSTOLOGY  OF   BODILY  EXERCISE. 

chapter  on  Combustions.  The  chemical  actions  which 
we  call  combustions,  profoundly  alter  the  structure  of 
the  tissues  at  the  expense  of  which  they  occur,  and  from 
this  change  result  new  products  which  stay  in  the  muscle 
for  a  certain  time. 

Now  these  products  exercise  on  muscle  a  peculiar 
action  which  paralyses  it  and  renders  its  contractiot] 
impossible.  If  we  submit  the  muscles  of  a  frog  to  the 
action  of  a  powerful  electric  stimulus,  and  prolong  this 
action  until  fatigue  is  complete,  that  is,  till  the  limbs  of 
the  animal  remain  motionless  under  the  most  powerful 
stimulation,  we  shall  have  in  the  fatigued  muscles  the 
elements  necessary  for  a  most  curious  experiment. 
Their  substance  rubbed  in  a  mortar,  and  made  into  a 
fine  soup,  contains  a  principle  capable  of  producing  in 
healthy  muscle  at  rest  the  fatigue  which  had  exhausted 
the  first  muscles.  If  we  inject  into  a  second  frog  this 
extract  of  fatigued  muscles,  we  bring  about  in  this 
animal  all  the  phenomena  of  fatigue,  and  its  limbs  v/ill 
fail  to  respond  to  electric  stimuli. 

Thus  there  are  developed  in  the  muscles,  in  the  very 
act  of  work,  certain  products  of  dissimilation  which  have 
the  power  of  doing  away  with  the  contractile  force  of 
the  muscle-fibres.  If  these  products  are  not  formed  in 
excessive  quantity,  they  are  rapidly  carried  off  by  the 
blood-current,  and,  if  not  renewed,  the  nutritive  disturb- 
ances produced  by  work  are  promptly  repaired.  If, 
however,  the  work  is  continued  too  long,  these  products 
accumulate  in  the  muscle  in  excessive  quantity.  They 
can  then,  for  a  time,  abolish  its  contractility,  and  may 
further  produce  serious  general  consequences,  of  which 
we  shall  speak  in  the  chapter  on  Overwork. 

We  must  then  conclude  that  the  pain  felt  in  a  muscle 
which  has  been  contracting  for  a  long  time,  results  from 
a  number  of  small  lesions,  stretchings  and  rubbings,  of 
the  sensitive  parts  of  the  region  which  has  been  working, 
and  that  the  absolute  powerlessness  which  we  notice 
is  due  to  a  nutritive  disturbance,  to  the  formation  within 
the   muscular   tissue   of  products   of  dissimilation,  the 


LOCAL  FATIGUE.  Ol 

contact   of  which   seems   to    paralyse    the    contractile 
element. 

We  must  also  say  that  the  powcrlessness  of  a  fatigued 
muscle  is  caused  in  part  indirectly  by  discomfort,  for  to 
make  it  contract  necessitates  a  painful  effort  of  the 
nervous  centres. 

The  phenomena  we  observe  in  the  laboratory  on 
stimulating  a  fatigued  muscle  by  means  of  electricity 
are  a  faithful  imitation  of  those  which  take  place  in  the 
system  when  the  will  endeavouis  to  put  in  action  a  limb 
which  has  become  powerless  after  excessive  work.  Just 
as  the  muscle  of  a  frog  which  has  been  fatigued  by 
excessive  discharges  needs  for  its  further  contraction  an 
increase  in  the  strength  of  the  stimulating  current,  so  in 
the  living  organism  an  increase  of  the  voluntary  stimulus 
is  necessary  to  throw  an  exhausted  arm  into  action,  and 
to  obtain  from  it  energetic  movements.  Now  the  will 
manifests  its  effort  by  a  disturbance  of  the  grey  matter 
of  the  brain,  and  when  this  disturbance  is  excessive  it 
becomes  painful. 

Local  fatigue  is  then  at  once  a  muscular,  and  a 
cerebral  phenomenon. 

The  fatigued  muscle  is  rendered  painful  by  the  friction 
to  which  it  is  subjected,  and  paralysed  in  its  contractile 
powers  by  the  contact  of  the  chemical  substances  which 
result  from  the  combustions  of  work.  The  brain  feels 
the  effects  of  fatigue  by  the  more  violent  disturbance 
which  the  voluntary  stimulus  produces  in  its  cells,  a 
stimulus  which  must  become  more  intense  in  proportion 
as  the  muscle  responds  less  readily. 

During  muscular  exercise,  the  sensation  of  fatigue  is 
sometimes  out  of  proportion  to  the  lesion  w4iich  the 
muscular  fibres  undergo,  and  to  the^  modifications  of 
nutrition  produced  in  it  by  the  work  it  has  performed. 
In  this  case  the  brain  has  become  exhausted  before  the 
muscle.  The  organ  of  will  seems  to  have  lost  part  of 
its  stimulating  power,  and  experiences  an  exaggerated 
sensation  of  fatigue.  The  man  has  no  longer  an  exact 
idea  of  the  energy  which  his  muscles  still  possess.  This 
is  what  we  observe  in  all  cases  in  which  a  depressing 
6 


62  PPIYSIOLOGY  OF  BODILY  EXERCISE. 

emotion  has  exercised  a  debilitating  influence  on  the 
nerve  centres. 

In  the  retreat  after  a  battle,  the  soldiers,  as  much 
demoralised  as  worn  out,  drag  themselves  painfully 
along.  The  state  of  depression  into  which  the  defeat 
has  thrown  them  makes  them  incapable  of  resisting  the 
uneasy  sensations  which  at  another  time  they  would 
hardly  have  noticed.  Their  swollen  feet,  their  wearied 
legs,  their  stiff  backs  prevent  them  from  moving. 
Groups  of  stragglers  loiter  along  :  every  one  is  dropping 
with  fatigue.  All  at  once  there  is  a  cry,  "  The  enemy  is 
upon  us  !  "  Immediately  they  all  find  their  legs  again. 
The  stiff  backs  are  straightened,  the  legs  are  stretched, 
the  limping  feet  are  vigorously  planted  on  the  ground, 
and  those  who  could  no  longer  even  walk,  are  seen  to 
run.  Their  muscles  had  not  lost  the  power  of  action, 
but  the  will  was  no  longer  a  sufficient  stimulus  to  set 
them  in  action.  A  more  powerful  one  was  needed  : 
Fear. 

In  some  cases  we  can  observe  converse  phenomena. 
A  violent  stimulation  of  the  nervous  centres  may,  after 
a  fashion,  galvanise  the  muscles,  as  would  a  very  power- 
ful electric  stimulus.  The  animal  can  then  force  from 
its  muscles  all  the  contractile  power  they  possess,  and 
continue  the  work  till  the  muscle  is  completely  ex- 
hausted, till  fa'tigue  is  absohite.  It  is  thus  when  a 
pressing  danger  obliges  a  man  or  an  animal  to  continue 
muscular  effort  in  spite  of  the  pain  which  it  causes.  A 
hunted  animal  runs  till  its  legs  can  no  longer  carry  it  ; 
when  it  drops,  its  muscles  are  fatigued,  in  the  physio- 
logical sense  of  the  word,  and  the  most  powerful  stimuli 
cannot  cause  them  to  contract.  But  the  work  necessary 
to  produce  complete  muscular  powerlessness  has  at  the 
same  time  produced  in  the  muscles  lesions  so  profound, 
and  such  grave  troubles  in  the  general  system,  that  the 
animal  hardly  ever  recovers  from  its  fatigue. 


LOCAL  FATIGUE.  63 


II. 


We  learn,  from  the  examples  quoted  above,  the 
essential  difference  between  subjective  fatigue,  that  which 
is  characterised  by  a  sensation,  and  objective  fatigue, 
which  consists  in  a  particular  state  of  the  muscles. 

Objective,  or  absolute  fatigue,  is  due  to  a  profound 
alteration  in  the  chemical  composition  of  the  muscles,  an 
alteration  wdiich  causes  these  organs  to  lose  the  power  of 
performing  their  ordinary  function. 

Subjective  fatigue  is  essentially  relative  and  variable, 
as  are  all  sensory  impressions.  It  consists  in  a  feeling  of 
discomfort,  or  a  slight  painful  sensation  in  muscle,  which 
results  from  a  very  superficial  modification  of  its 
structure. 

In  the  ordinary  phenomena  of  muscular  exercise, 
fatigue  is  never  absolute,  and  the  cases  in  w^hich  a  man 
really  exhausts  all  the  contractile  force  of  his  muscles 
are  very  rare.  The  sensation  of  fatigue  prevents  a  man 
from  having  an  exact  idea  of  the  energy  which  his 
muscular  fibres  still  possess,  and  induces  repose  long 
before  all  the  force  of  the  motor  organs  has  been 
expended.  Similarly  the  sensation  of  hunger  warns  us 
that  the  body  needs  food  long  before  the  system  is 
enfeebled  for  lack  of  nourishment. 

We  may  say  that  the  sensation  of  fatigue  puts  us  on 
guard  against  a  danger.  It  would  in  fact  be  dangerous 
to  continue  working  until  the  muscles  were  completely 
exhausted,  until  the  moment  w^hen  they  becam.e 
incapable  of  contracting,  for  these  organs  would  then 
have  undergone  such  profound  disturbances  of  nutrition 
as  to  endanger  the  entire  organism,  as  occurs  in  the 
hunted  animal. 

Fatigue  is  then,  in  the  ordinary  actions  of  life,  a  kind 
of  regulator,  warning  us  that  we  are  exceeding  the 
limits  of  useful  exercise,  and  that  work  will  soon  become 
dangerous. 

Numerous  physiological  phenomena  show  us  that  the 


64  PHYSIOLOGY  OF   BODILY  EXERCISE. 

sensation  of  fatigue  has  its  seat  rather  in  the  nervC' 
centres  than  in  the  muscles.  Whenever  muscular  work 
is  performed  without  the  brain  taking  part  in  it,  we 
notice  that  fatigue  is  much  more  slowly  produced  ;  while 
it  is  more  intensely  manifested  the  more  vigorously  the 
cerebral  faculties  are  associated  in  the  performance  of 
the  action. 

Many  movements  are  involuntary  and  unconscious  ; 
the  movements  of  organic  life,  the  heart-beat,  the 
respiratory  movements.  None  of  these  movements, 
which  are  performed  without  the  intervention  of  the 
brain,  and  independently  of  the  will,  ever  determine  the 
sensation  of  fatigue. 

At  each  contraction  the  heart  exercises  a  force  capable 
of  raising  through  a  height  of  one  centimetre  a  weight 
of  forty  kilogrammes,  and  it  contracts  sixty  times  per 
minute.  Which  of  our  limbs  could  carry  on  such  a 
labour  for  a  quarter  of  an  hour  ?  We  may  say  the 
same  of  the  muscles  which  bring  about  the  respiratory 
movements.  They  contract  sixteen  times  per  minute 
and  never  rest  ;  they  work  incessantly  from  birth  till 
death,  and  never  become  fatigued. 

The  muscles  ordinarily  under  the  control  of  the  will 
have  the  same  immunity  from  fatigue  when  their  con- 
traction is  involuntary.  In  hysterical  contracture,  in 
catalepsy,  in  hypnotism,  the  patient,  whose  will  is  not  in 
action,  easily  supports  the  most  fatiguing  positions  with- 
out being  fatigued.  In  chorea,  or  St.  Vitus'  dance,  we 
see  the  patients  making  violent  movements  without 
intermission  from  morning  till  night.  A  man  who 
endeavoured  to  perform  the  same  movements  voluntarily 
would  have  to  stop  to  rest  in  a  very  short  time.  But 
these  patients  do  not  complain  of  the  sensation  of 
fatigue. 

Thus  the  same  muscular  work  which  produces  fatigue, 
when  it  is  voluntary,  no  longer  produces  it  when  it  is 
done  without  the  intervention  of  the  will,  that  is,  when 
the  brain  does  not  associate  in  the  performance  of  the 
muscular  action. 

The  brain  then,  is  most   probably  the  seat  of  that 


LOCAL   FATIGUE.  65 

sensation  which  causes  cessation  of  work  before  the 
muscles  are  really  fatigued.  In  voluntary  movements, 
the  more  intimate  the  association  of  the  brain  with  the 
muscular  action,  the  more  intense  the  sensation  of 
fatigue.  An  exercise  which  is  accompanied  by  a  con- 
siderable tension  of  the  will  is  more  fatiguing  than  one 
performed  independently  of  the  will.  Sometimes  work 
which  needs  an  insignificant  expenditure  of  force,  causes 
very  prompt  lassitude  when  it  is  executed  with  a 
sustained  attention,  that  is  to  say  when  the  will  is  not 
relaxed  for  an  instant. 

A  man  taking  riding-lessons  becomes  much  more  tired 
in  the  narrow  limits  of  the  riding-school  than  he  would 
by  riding  a  long  distance  at  a  trot.  In  the  first  case  the 
will  must  preside  with  a  vigilant  care  over  all  the  actions 
of  the  horseman's  legs,  and  over  the  reins.  In  the 
second  case,  the  body,  accustomed  to  the  horse's  paces, 
automatically  accommodates  itself  to  the  movements  of 
trotting,  and  the  brain  takes  no  part  in  the  exercise. 

Few  things  vary  as  much  as  the  susceptibility  of 
different  persons  to  fatigue.  Very  nervous  and  very 
irritable  individuals  feel  sometimes  too  keenly  the 
painful  sensations  which  accompany  muscular  work, 
and  they  are  then  placed  in  this  dilemma  :  whether  to 
stop  when  fatigue  is  first  felt,  and  do  less  exercise  than 
they  really  require,  or  to  resist  fatigue  and  expose  them- 
selves to  the  nervous  reaction  which  follows,  in  such 
persons,  any  considerable  pain.  Nervous  hyperexcit- 
ability  often  results  from  the  struggle  of  an  enfeebled 
man  against  the  discom^fort  which  work  causes  him,  and 
compels  the  doctor  to  forbid  exercise  to  such  a  patient, 
to  whom  it  would  be  most  valuable  if  it  could  be 
endured. 

In  these  cases  we  can  always  manage  to  make 
exercise  supportable,  but  it  is  necessary  carefully  to 
consider  the  form  under  which  it  will  have  the  best 
chance  of  being  borne,  that  is  to  say  the  form  which  will 
cause  least  fatigue. 

We  can  here  only  indicate  broadly  how  to  proceed  in 


66  PHYSIOLOGY  OF   BODILY  EXERCISE. 

such  cases,  in  which  medication  by  exercise  needs  much 
tact,  and  a  profound  study  of  each  exercise  performed. 
Here  we  shall  only  formulate  this  law  : 

T/ie  muscular  work  being  equals  the  sensation  of 
fatigue  is  the  more  intense,  the  more  active  the  inter- 
vention of  the  cerebral  faculties  demanded  by  the 
exercise. 

Consequently,  in  dealing  with  very  nervous  persons, 
it  will  be  necessary  to  employ  exercises  which  do  not 
need  a  sustained  attention,  those  of  which  the  move- 
ments are  easy,  and  as  much  as  possible,  automatic  ; 
walking,  foi  instance. 


CHAPTER  IL 

B  RE  ATHLESSNESS. 

A  Hard  Run — Exercises  which  cause  Loss  of  Breath  ;  Trotting 
and  Galloping  ;  Going  Upstairs — Law  of  Breathlessness — 
Respiratory  Need  ;  Conditions  under  which  it  Increases  and 
Diminishes — Carbonic  Acid  ;  its  Production  Increases  with 
Muscular  Activity  ;  it  Diminishes  during  Repose — The  Sleep 
of  the  Marmot — Explanation  of  the  Law  of  Breathlessness — 
Why  we  lose  Breath  in  Running — Why  the  Horse  Gallops 
with  its  Lungs — Why  Exercises  of  the  Legs  cause  more  Loss 
of  Breath  than  those  of  the  Arms — The  Coefficiejit  of  Breath- 
lessness— The  Horse  which  exceeds  its  Paces — Breathlessness 
is  an  Auto-Intoxication  by  Carbonic  Acid — Analogy  with 
Asphyxia — Impossibility  of  Fighting  against  Breathlessness. 

Have  you  ever  found  yourself  within  sight  of  the 
station  and  been  afraid  of  missing  the  train  ?  You  have 
a  quarter  of  a  mile  to  traverse,  and  you  see  from  your 
watch  that  you  have  only  two  minutes.  You  will  have 
to  run,  and  for  years  you  have  been  accustomed  to  the 
measured  pace  of  the  man  who  walks  when  he  has 
plenty  of  time  and  takes  a  cab  when  he  has  not.  But 
you  want  to  catch  that  train,  and  plucking  up  courage 
you  set  off  as  hard  as  you  can  run. 

Your  legs  are  strong  and  it  does  not  hurt  them  when 
you  run.  However,  after  a  few  seconds,  a  peculiar 
distress  seizes  you.  Your  breathing  is  embarrassed,  a 
weight  seems  to  press  you  dc  w  i,  and  a  bar  to  be  fixed 
on  your  chest.  Your  respiratory  movements  become 
jerky  and  irregular.  With  each  step  distress  increases 
and  becomes  more  general.  Your  temples  throb 
violently,  an  insupportable  heat  rises  to  your  brain,  an 
iron  band  is  tied  round  your  forehead.  Then  there  is  a 
singing  in  your  ears,  your  sight  is  disturbed,  and  you 


68  PHYSIOLOGY  OF   BODILY   EXERCISE. 

have  but  a  confused  idea  of  the  objects  you  pass,  and  of 
the  people  who  turn  to  stare  at  your  pale  and 
dishevelled  figure. 

You  reach  your  goal.  As  the  train  whistles  you  sink 
exhausted  on  the  cushions  of  your  compartment. 
There,  in  spite  of  the  satisfaction  of  having  caught  your 
train,  and  the  solace  of  being  seated,  your  distress  con- 
tinues. Still  for  some  minutes  you  are  out  of  breath, 
and  the  hurried  movements  of  your  chest  make  you 
resemble  a  man  seized  with  a  violent  attack  of  asthma. 

This  is  what  we  call  "  being  winded'' 

We  are  seldom  astonished  by  things  which  we  see 
every  day,  and  it  seems  natural  to  every  one  that  a  man 
should  be  out  of  breath  when  he  has  been  running. 
But  if  we  think  about  the  matter,  there  is  something 
surprising  in  the  phenomenon  of  breathlessness  while 
running  :  when  we  run  the  legs  do  the  work  and  the 
lungs  become  fatigued. 

I. 

No  methodical  exposition  and  rational  explanation  of 
breathlessness  have  hitherto  been  given.  This  form  of 
fatigue  has  not  as  yet  been  the  subject  of  any  mono- 
graph ;  it  is  not  described  in  any  great  dictionary  of 
medicine  nor  in  any  physiological  text-book. 

There  is  however,  no  phenomenon  more  common  and 
more  frequently  observed  than  breathlessness  ;  there  is 
none  more  interesting  from  the  point  of  view  of  the 
hygienic  and  therapeutical  results  of  muscular  exercise. 

Breathlessness  is  a  feeling  of  distress  which  is  pro- 
duced during  violent  exercise  or  intense  muscular  work, 
and  it  is  characterised  by  an  exaggeration  of  the  respi- 
ratory need,  and  by  profound  disturbance  in  the  func- 
tions of  the  respiratory  organs.  This  state  is  merely  a 
peculiar  form  of  dyspnoea  and  presents  the  general  pheno- 
mena due  to  deficient  aeration  of  the  blood.  But  it  differs 
from  the  respiratory  troubles  which  we  notice  in  morbid 
conditions  by  certain  special  signs  which  we  shall  point 
out,  and  above  all  in  the  conditions  in  which  it  is  pro- 
duced and  in  the  mechanism  of  its  production. 


BREATH  LESS  NESS.  69 

If  we  try  to  determine  în  what  conditions  breathless- 
ness  is  produced  during  work,  we  are  struck  first  by  the 
fact  that  certain  exercises,  certain  movements,  seem  to 
have  the  privilege  of  influencing  more  promptly  than 
others,  the  respiratory  functions. 

In  certain  muscular  actions  fatigue  takes  the  form  of 
breathlessness,  and  respiratory  distress  forces  the  indi- 
vidual to  stop  working  long  before  the  muscles  are 
fatigued.  A  man  running,  or  rapidly  going  up-stairs, 
is  forced  to  stop,  not  to  rest  his  legs,  but  to  take  breath. 

In  other  exercises,  on  the  other  hand,  the  muscles  are 
fatigued  and  refuse  to  go  on  working  long  before  breath- 
lessness occurs.  Going  along  a  hanging  ladder  by  the 
hands  only,  dumb-bell  exercise,  holding  out  weights  at 
arms'  length,  are  movements  which  quickly  fatigue  the 
limbs  without  causing  any  marked  disturbance  in  the 
respiratory  functions.  When  we  are  obliged  to  stop 
these  exercises  it  is  not  because  we  are  short  of  breath, 
but  because  our  muscular  force  is  expended. 

In  animals  it  has  been  noticed  that  certain  paces,  cer- 
tain forms  of  work,  more  particularly  produce  breath- 
lessness, while  others  rather  produce  fatigue  of  the  limbs. 

Trainers  say,  "  A  horse  trots  with  its  legs  and  gallops 
with  its  lungs."  This  phrase  expresses  well,  with  its 
humorous  figure,  the  importance  of  pace  in  the  produc- 
tion of  breathlessness.  Why  is  a  horse  more  out  of 
breath  after  a  gallop  than  after  a  trot  ?  Our  first  idea  is 
to  attribute  the  more  prompt  breathlessness  to  greater 
swiftness.  But  we  must  not  confound  pace  with  speed. 
The  pace  of  galloping  is  not  incompatible  with  very  little 
speed.  We  can  slow  down  the  gallop  of  a  horse  till  it 
falls  behind  another  horse  which  is  trotting.  There  are 
animals  so  awkward  that  their  gallop  is  as  slow  as  a 
walk.  Now,  however  slow  a  gallop  may  be,  it  will  more 
quickly  make  a  horse  out  of  breath  than  an  equally  rapid 
trot. 

Breathlessness  is  not  then  produced  under  the  same 
conditions  as  local  muscular  fatigue,  and  certain  exer- 
cises seem  to  have  the  privilege  of  influencing  respiration. 

W^hen  we  try  to  find  the  explanation   of  this  fact,  we 


^0  PHYSIOLOGY   OF   BODILY   EXERCISE. 

naturally  ask  at  the  outset  whether  the  exercises  which 
cause  loss  of  breath  have  not  a  direct  influence  on  the 
organs  which  execute  the  respiratory  movements,  whether 
they  do  not  require,  for  example,  that  the  muscles  of  the 
chest  and  back  should  be  involved,  the  contraction  of 
these  muscles  interfering  with  the  action  of  the  ribs. 
But  this  hypothesis  is  discredited  at  the  first  glance,  for 
the  exercises  which  in  man  cause  most  breathlessness 
are  not  those  which  demand  work  from  the  upper  limbs, 
and  consequently  the  direct  concurrence  of  the  thoracic 
muscles.  Running,  leaping,  going  up  a  steep  ascent,  are, 
of  all  known  exercises,  those  which  most  quickly  cause 
loss  of  breath,  and  they  are  executed  by  the  legs,  the 
muscles  of  which  are  not  attached  above  the  pelvis,  and 
have  consequently  no  direct  action  on  the  thorax. 

We  believe  it  to  be  impossible  to  explain  the  tendency 
of  this  or  that  muscular  exercise  to  produce  breathless- 
ness, if  we  direct  our  attention  solely  to  the  peculiarities 
of  movement  and  attitude  which  these  exercises  render 
necessary. 

Certain  authors,  who  have  incidentally  referred  to 
breathlessness,  seem  to  attribute  this  form  of  fatigue  to 
the  very  mechanism  of  the  exercises  which  cause  it,  and 
to  the  direct  disturbance  which  these  exercises  produce 
in  the  respiratory  movements. 

"  Breathlessness  in  running  occurs  because  the  runner, 
unable  to  make  the  deep  and  prolonged  inspirations 
necessary  for  the  continuance  of  his  efforts,  endeavours 
to  make  up  for  this  by  frequency  of  respiratory  move- 
ments, so  that  he  can  fix  as  firmly  as  possible  his  verte- 
bral column  and  his  thorax."  * 

We  quote  this  opinion  to  show  how,  as  a  rule,  authors 
who  have  written  about  muscular  exercise  have  made 
what  seemed  to  them  reasonable  deductions,  rather  than 
direct  observation  of  facts.  In  fact,  Michel  Levy's  view 
is  based  upon  an  error  of  observation  which  anyone  can 
verify  personally  if  he  is  not  afraid  to  run  for  a  minute 
or  two.  In  a  man  running  it  is  not  inspiration  which  is 
difficult,  it  is  expiration.  In  this  exercise  we  experience 
•  Michel  Levy.    Traité  d'hygiène. 


BREATHLESSNESS.  7I 

no  difficulty  in  getting  air  into  the  chest  :  it  is,  on  the 
contrary,  the  exit  of  air  which  is  difficult  and  incomplete. 
According  to  observations  which  we  have  made  on  our- 
selves and  on  a  friend  who  willingly  lent  himself  to  this 
study,  inspiration  is  free,  easy,  deep,  and  three  times  as 
long  as  expiration.  The  latter,  on  the  other  hand,  is 
short,  insufficient,  and  leaves  the  impression  of  an  un- 
satisfied want. 

IMoreover,  the  very  peculiar  rhythm  of  respiration  in  a 
man  running  is  not  due  to  the  mechanism  of  the  exercise, 
for  we  have  the  same  rhythm  in  all  exercises,  of  whatever 
nature,  which  produce  breathlessness,  and,  moreover,  it 
always  persists  a  long  time  after  the  exercise  has  been 
discontinued.  We  cannot  then  say  that  this  mode  of 
respiration  is  due  to  muscular  contractions,  or  to  forced 
attitudes,  for  we  still  observe  it  when  all  the  muscles  are 
relaxed  and  the  body  is  in  the  attitude  of  repose. 

The  derangement  of  respiration  in  all  the  exercises 
which  produce  breathlessness  is  not  the  prime  cause  of 
dyspnœa  ;  on  the  contrary,  it  is  the  effect  of  it.  The 
explanation  of  breathlessness,  based  on  the  mechanical 
hindrance  to  the  respiratory  movements,  is  far  from 
being  applicable  to  all  the  exercises  which  produce  it, 
and  to  all  the  circumstances  of  breathlessness. 

If  we  look  for  a  condition  common  to  all  the  muscular 
actions  said  to  be  capable  of  rapidly  producing  respira- 
tory troubles,  w^e  are  struck  by  the  fact  that  all  necessi- 
tate a  very  great  expenditure  of  force  in  a  very  short 
period  of  time.  This  we  believe  to  be  the  essential  con- 
dition of  breathlessness. 

There  are  other  conditions  favouring  the  occurrence 
of  respiratory  distress  during  an  exercise,  such  as  a 
momentary  suspension  of  respiration,  as  we  see  in  the 
phenomenon  of  effort,  or  a  forcing  of  the  thoracic 
muscles  to  associate  in  an  exercise  in  a  way  to  pre- 
vent them  from  fulfilling  their  respiratory  function.  But 
these  conditions  have  merely  a  passing  influence,  and 
contribute  but  little  to  the  production  of  breathlessness. 
The  causes  capable  of  mechanically  hindering  respiration 
intervene  as  accessory  factors,  as  a  complication  capable 


72  PHYSIOLOGY  OF   BODILY  EXERCISE. 

of  accelerating  the  onset  and  of  aggravating  breathless- 
ness  ;  but  they  alone  cannot  induce  a  prolonged  and  per- 
sistent hindrance  to  respiration,  nor  unless  they  are  asso- 
ciated with  muscular  actions  needing  a  great  deal  of  work. 

To  be  convinced  of  this,  it  is  only  necessary  to  imitate 
experimentally  what  occurs  in  certain  muscular  actions 
which  cause  suspension  of  respiration. 

If  we  take  a  deep  breath,  and  after  closing  the  glottis, 
vigorously  compress  the  air  in  the  chest  by  contracting 
the  expiratory  muscles,  we  are  placed  in  all  the  physio- 
logical conditions  oi effort.  The  face  injected  with  blood, 
the  veins  of  the  neck  standing  out,  the  ribs  strongly 
raised,  the  thorax  motionless  in  the  position  of  forced 
inspiration,  give  a  complete  picture  cf  the  phenomena 
presented  by  a  man  who  is  raising  a  load  from  the  ground 
on  to  his  shoulders.  But  the  load,  and  the  expenditure 
of  muscular  force  which  it  renders  necessary,  are  want- 
ing. Hence,  in  spite  of  the  complete  suspension  of  re- 
spiration, breathlessness  is  not  produced  by  a  great 
number  of  simulated  efforts,  while  it  is  always  produced 
by  a  very  small  number  of  real  efforts,  accompanied  by 
intense  muscular  work. 

That  which  causes  breathlessness  after  effort  is  the 
quantity  of  work  done  and  not  the  particular  attitude 
which  this  work  demands,  and  the  momentary  interrup- 
tion of  respiration  which  results  from  it.  It  is  because 
they  have  not  analysed  these  two  elements  in  a  complex 
action  that  many  authors  have  attributed  the  breathless- 
ness produced  by  certain  exercises  to  the  momentary 
suspension  of  respiration  during  effort.  Even  complete 
suspension  of  respiration  cannot,  acting  alone,  produce 
the  phenomena  we  observe  in  persons  who  are  out  of 
breath.  It  produces  respiratory  distress,  which  lasts  as 
long  as  the  function  is  suspended  ;  but  as  soon  as  the 
movements  become  free  again  the  distress  ceases,  and 
respiration  immediately  assumes  its  regular  rhythm. 

Breathlessness,  on  the  contrary,  lasts  for  a  long  time 
after  the  exercise  is  over,  and  this  proves  that  it  has  a 
more  profound  and  more  lasting  cause  than  a  momentary 
arrest  of  the  respiratory  functions. 


BREATHLESSNESS.  73 

If  we  pass  in  review  all  the  exercises  which  seem 
especially  to  produce  breathlessness,  and  submit  them  to 
a  careful  analysis,  we  find  everywhere  a  confirmation  of 
the  law  which  connects  the  sensation  of  great  respiratory 
distress  with  the  expenditure  of  a  large  amount  of  force 
in  a  short  time. 

Let  us  analyse  one  of  the  simplest  actions,  that  of 
going  upstairs.  No  work  more  rapidly  causes  breath- 
lessness than  this,  but  none  causes  greater  expenditure 
of  force. 

Let  us  suppose  that  a  man  is  going  at  a  moderate 
pace  up  two  flights  a  minute,  so  as  to  take  two  minutes 
in  going  up  four  flights  of  a  height  of  20  metres  in  all. 
Let  him  weigh  75  kilogrammes,  and  he  will  in  two 
minutes  have  raised  75  kilogrammes,  20  metres,  and 
thus  have  executed  work  of  75x20=1,500  kilogram- 
metres. 

If  we  reduce  to  another  form  the  total  quantity  of 
work  expended  in  going  up  the  stairs,  we  are  astonished 
to  see  that  if  we  were  lifting  weights,  it  would  be 
necessary  in  order  to  do  the  same  amount  of  work,  to 
take  successively  30  weights  of  50  kilogrammes  each, 
and  place  them  on  a  table  one  metre  from  the  ground, 
and  this  within  two  minutes. 

It  is  evident  that  work  such  as  this  is  very  violent 
exercise,  but  to  go  up  four  flights  of  stairs  is  so  common, 
that  we  do  not  think  of  asking  how  much  force  it 
needs.  Similarly  with  all  the  exercises  by  which  the 
body  is  raised,  such  as  climbing  a  hill.  In  all  these 
cases  the  human  body,  a  considerable  weight,  has  in 
going  up  an  inclined  plane,  been  displaced  more  or  less 
in  height,  and  this  displacement  needs  a  great  expendi- 
ture of  force. 

Similarly  if  we  study  what  passes  in  a  man  running  : 

At  every  step  there  is  an  instant  when  both  feet  are 
off  the  ground,  and  the  body  is  in  a  sense  launched 
through  space,  without  being  sustained  by  the  legs,  by 
reason  of  the  muscular  impulse  which  lifted  it  from  the 
ground.  This  impulse,  which  represents  an  enormous 
amount  of  v/ork,  is  renewed  three  or  four  times  a  second 


74  PHYSIOLOGY  OF  BODILY   EXERCISE. 

While  walking,  on  the  contrary,  the  body  is  supported 
by  the  feet  and  never  leaves  the  ground.  These  details 
show  clearly  the  great  difference  of  work  represented  by 
the  pace  of  walking  and  that  of  running. 

Let  us  note  that  in  running,  breathlessness  is  due  less 
to  the  swiftness  than  to  the  mode  of  progression,  to  the 
manner  in  which  the  body  is  moved.  Swiftness  of 
movement  does  not  suffice  to  produce  breathlessness 
unless  combined  with  intensity  of  muscular  effort.  So 
we  must  not  use  the  swiftness  of  an  exercise  to  form 
a  judgment  of  the  amount  of  breathlessness  it  ought  to 
produce. 

It  is  possible,  as  we  have  said,  to  slow  the  gallop  of  a 
horse  so  as  to  render  it  less  rapid  than  a  long-stepping 
trot,  but  all  the  same  we  find  that  the  animal  becomes 
much  more  breathless  galloping  than  trotting.  This  is 
because  the  gallop  of  the  horse  is  a  much  higher  pace 
than  the  trot,  as  the  experiments  of  Marey  have  shown. 
The  galloping  horse  raises  its  body  to  a  greater  height 
from  the  ground  than  a  trotting  horse,  and  consequently 
performs  a  greater  quantity  of  mechanical  work.  It  is 
because  of  this  difference  in  the  quantity  of  force  ex- 
pended that  a  trot  of  equal  swiftness  always  makes  the 
animal  less  breathless  than  a  gallop. 

It  would  be  easy  to  multiply  examples.  Those  we 
have  given  suffice  to  demonstrate  that  the  true  condition 
of  breathlessness,  that  in  which  respiratory  distress  is 
produced  for  a  considerable  time,  is  the  great  expendi- 
ture of  force  rendered  necessary  by  an  exercise  in  a 
given  time.     Other  things  being  equal,  we  can  say  : — 

In  every  muscular  exercise,  the  intensity  of  breathless' 
ness  ÎS  in  direct  ratio  to  the  quantity  of  force  expeiidcd  in 
a  given  ilme. 

Breathlessness  is  a  general  effect,  a  resultant.  It  is 
the  effect  of  the  total  quantity  of  work  performed  by  the 
muscles  which  concur  in  an  exercise. 

Muscular  fatigue,  on  the  other  hand,  is  a  local  effect. 
It  is  in  direct  proportion  to  the  share  in  the  work  taken 
by  each  muscle  used  in  the  exercise. 


BREATHLESSNESS.  75 

An  amount  of  work  too  small  to  induce  breathless- 
ncss  can  produce  fatigue  if  the  effort  is  performed  by 
a  small  number  of  muscles,  or  by  very  weak  muscular 
groups.  If,  on  the  contrary,  the  exercise  is  divided 
among  a  great  number  of  muscles,  or  performed  by 
very  powerful  muscular  masses,  the  part  of  the  work 
performed  by  each  contractile  fasciculus  will  be  too 
small  to  induce  local  fatigue,  while  the  sum  represented 
by  the  work  of  each  may  be  sufficient  to  induce  breath- 
lessness. 

Breathlessness  is  a  general  form  of  fatigue.  When 
we  wish  to  obtain  from  muscular  exercise  its  general 
effects^  we  must  seek  exercises  which  cause  breathlessness, 
and  not  confine  ourselves  to  those  which  cause  fatigue. 
The  effects  of  the  latter  are  especially  local. 

Finally,  in  the  dosage  of  muscular  exercise,  we  can 
consider  breathlessness  as  a  kind  of  physiological 
measure  indicating  more  surely  than  muscular  fatigue 
the  intensity  of  the  work  to  which  the  organism  has 
been  submitted.  When  breathlessness  has  not  been 
produced,  we  can  say  that  the  exercise  has  been 
moderate,  or  at  least  that  it  has  been  taken — if  one  may 
so  express  it — in  fractional  doses.  Whenever,  on  the 
contrary,  respiratory  distress  is  promptly  produced,  we 
can  affirm  that  a  great  quantity  of  work  has  been  done 
in  a  short  time,  and  consequently  that  the  exercise  has 
been  taken  in  large  doses. 

Certain  exercises  which,  at  -first  sight,  appear  moderate, 
will  be  considered  properly  to  be  violent  exercises,  if  we 
submit  them  to  the  above  criterion. 

Thus  it  is  that  a  girl  dancing  on  the  tight-rope  is 
really  performing  a  more  violent  exercise  than  an  oars- 
man rowing,  or  a  gymnast  on  the  trapeze. 

Thus,  to  sum  up,  if  certain  exercises  cause  breathless- 
ness more  than  others,  this  result  is  not  due  to  special 
movements  or  to  particular  attitudes  w^hich  they 
occasion.  The  quick  advent  of  breathlessness  is  not 
due  to  the  contraction  of  certain  muscles,  to  the  displace- 
ment of  certain  bony  levers,  to  the  mechanical  disturb- 
ance which  certain  organs  undergo  during  exercise  :  W 


;6  PHYSIOLOGY  OF   BODILY  EXERCISE. 

Î.S  due  to  the  excessive  expenditure  of  force  which  the 
exercise  necessitates. 

It  was  important  clearly  to  establish  the  conditions 
under  which  breathlessness  is  produced,  for  from  these 
conditions  we  are  about  to  deduce  the  real  cause  of 
breathlessness. 

n. 

When  a  breathless  man  seeks  to  study  hirnself,  and 
to  analyse  the  tumultuous  sensations  he  experiences,  he 
finds  himself  much  embarrassed  exactly  to  characterise 
his  distress,  and  accurately  to  localise  it  in  this  or  that 
part  of  his  body.  One  impression,  however,  dominates 
all  the  others,  and  sums  them  up  aptly  enough  :  it  is 
the  feeling  of  an  increased  respiratory  need,  which  he  is 
unable  to  satisfy. 

This  increase  of  the  respiratory  need  is  the  funda- 
mental character  of  breathlessness. 

In  what  does  respiratory  need  consist,  in  what  condi- 
tions is  it  produced,  why  does  increase  of  muscular  work 
induce  an  increase  of  this  need  ?  These  are  the 
questions  we  have  to  answer  in  order  to  understand  the 
connection  between  breathlessness  and  the  muscular 
exercise  which  causes  it. 

The  respiratory  need  is  a  kind  of  regulator  of  the 
respiratory  function.  It  is  a  sensation  which  forces  the 
individual  to  increase,  more  or  less,  the  frequency  and 
amplitude  of  the  thoracic  movements,  according  to  the 
greater  or  less  need  of  the  system  for  the  aeration  of 
the  blood,  that  is  to  say,  for  giving  to  venous  the 
qualities  of  arterial  blood,  by  replacing  the  excess  of 
carbonic  acid,  contained  in  the  former,  by  oxygen 
derived  from  the  atmospheric  air. 

Neither  hunger,  nor  thirst,  nor  any  other  natural 
appetite  produces  a  disturbance  in  the  system  as  rapidly 
as  the  respiratory  need  when  it  is  not  satisfied.  No 
other  appetite  is  bound  up  so  intimately  with  the  safety 
of  the  organism. 

Respiration,  in  fact,  has  to  defend  us  from  a  very 
pi^cssing  danger,  by  eliminating  carbonic  acid  from  the 


BREATIILESSNESS.  JJ 

blood,  a  poison,  the  accumulation  of  which  in  the  body 
can  cause  death  in  a  few  minutes. 

Carbonic  acid  is  a  product  of  dissimilation,  resulting 
from  vital  combustions.  It  is  incessantly  formed  in  the 
organism,  as  long  as  animal  heat  is  being  produced,  that 
is,  as  long  as  life  lasts.  If  the  system  usually  suffers  no 
ill  effects  from  this  poison,  it  is  because  it  is  constantly 
eliminated  by  the  lungs. 

The  system  can  bear,  without  detriment,  a  definite 
dose  of  carbonic  acid.  When  that  dose  is  exceeded, 
distress  is  immediately  produced.  This  is  called  respi- 
ratory need,  dyspnœa,  and  is  a  warning  to  us  that  the 
toxic  substance  is  accumulating  in  the  blood. 

The  presence  of  an  excess  of  carbonic  acid  in  the 
blood  is  the  cause  of  the  sensation  w^hich  instinctively 
urges  us,  sometimes  even  against  our  will,  to  render 
more  active  the  play  of  the  respiratory  apparatus. 

All  the  circumstances  which,  cause  more  or  less 
variation  in  the  quantity  of  carbonic  acid  in  the  blood 
cause  also  more  or  less  variation  in  the  intensity  of  the 
respiratory  need,  and  in  the  frequency  of  the  respiratory 
movements — the  sign  by  which  the  need  is  externally 
made  manifest. 

Whenever  the  organism  produces  less  carbonic  acid 
than  usual,  the  respiratory  need  diminishes,  and  the 
respiratory  movements  become  slower.  We  observe 
this  during  sleep.  A  sleeping  man  produces  less  car- 
bonic acid  than  one  awake  ;  his  respiration  is  also  less 
frequent.  More  especially  in  the  sleep  of  hibernating 
animals  we  can  observe  the  very  intimate  correlation 
between  the  diminution  of  carbonic  acid  in  the  economy, 
and  the  lessening  of  the  respiratory  need. 

According  to  the  curious  experiments  of  Regnault, 
the  production  of  carbonic  acid  in  a  hibernating  marmot 
is  one-thirtieth  of  that  which  occurs  when  the  animal  is 
awake.  Also  he  observed  a  surprising  diminution  in  the 
respiratory  need  of  the  hibernating  animal.  On  waking, 
the  production  of  carbonic  acid  quickly  increases,  and  at 
the  same  time  the  exigencies  of  respiration  resume  all 
their  intensity. 
7 


78  PHYSIOLOGY   OF   BODILY   EXERCISE. 

A  hibernating  marmot  was  placed  under  a  very  small 
bell-glass,  the  edge  of  which  was  cemented  to  the  table 
on  which  the  apparatus  was  placed.  In  this  manner  the 
access  of  the  external  air  to  the  jar  was  prevented,  and 
the  respiration  of  the  animal  was  confined  to  the  very- 
small  quantity  of  air  contained  in  its  prison.  As  long 
as  its  sleep  lasted,  its  respiration  was  sufficient,  and  the 
animal  was  able  to  live  for  several  days  on  this  almost 
infinitesimal  quantity  of  oxygen,  without  giving  any 
sign  of  distress.  One  day  the  marmot  was  awakened  by 
a  violent  blow  on  the  bell-glass.  The  animal  was  hardly 
awakened  before  it  manifested  by  its  agitation,  and  by 
the  disordered  movements  of  its  thorax,  a  great  respira- 
tory need,  and  died  of  asphyxia  in  a  few  minutes.  The 
quantity  of  air  which  sufficed  to  support  its  life  before  it 
was  awakened  was  no  longer  enough  when  aroused  from 
hibernation.  The  awakening  had  suddenly  increased 
the  acti\'ity  of  the  organism,  increased  the  production  of 
carbonic  acid,  and  the  saturation  of  the  blood  with  this 
gas  had  increased  the  needs  of  respiration  so  much  that 
the  small  quantity  of  air  in  the  bell  could  no  longer 
satisfy  them. 

If  the  respiratory  need  diminishes  when  the  pro- 
portion of  carbonic  acid  in  the  blood  is  less  than  usual, 
it  increases,  on  the  other  hand,  whenever  this  gas  becomes 
more  plentiful.  If  the  quantity  of  carbonic  acid  becomes 
very  large,  the  respiratory  need  assumes  the  character 
of  intense  dyspnœa,  of  severe  suffering,  and  provokes 
more  and  more  energetic  and  frequent  respiratory 
movements. 

If  we  inject  carbonic  acid  into  the  veins  of  a  dog,  its 
respiration  is  quickened,  becomes  oppressed,  anxious  ; 
the  animal  manifests  greater  and  greater  respiratory 
distress.  If  we  continue  the  injection  the  symptoms 
become  continually  more  grave  until  the  animal  finally 
dies  with  all  the  phenomena  of  asphyxia.  No  experi- 
ment can  invalidate  this.  It  definitely  proves  that  the 
respiratory  need  increases  when  there  is  an  excess  of 
carbonic  acid  in  the  blood,  and  not  only — as  some  have 
urged — when  there  is  too  small  a,  quantity  of  oxygen. 


BREATHLESSNESS.  79 

In  fact,  in  the  example  we  have  given,  the  air  passages 
of  the  dog  were  free,  there  was  nothing  to  prevent  a 
normal  quantity  of  the  oxygen  of  the  air  from  reaching 
its  lungs  ;  but  dyspnoea  ensued  and  the  animal  died  of 
asphyxia. 

The  respiratory  need  is  then  proportional  to  the 
quantity  of  carbonic  acid  in  the  blood. 

Many  conditions  in  man  can  bring  about  an  accumu- 
lation of  carbonic  acid  in  the  economy.  It  can  be 
introduced  from  without  through  the  air-passages,  and 
we  then  see  accidents  similar  to  those  which  we  have 
just  described  in  the  experiment  on  the  dog.  In  this 
manner  the  emanations  from  a  brewing  vat  produce 
death  by  asphyxia. 

Similar  accidents  occur  when  the  carbonic  acid,  in- 
stead of  being  introduced  into  the  system  from  without, 
is  simply  retained  there  by  some  hindrance  to  the 
eliminating  power  of  the  lungs.  Thus  when  a  child  dies 
of  croup,  it  is  asphyxiated  by  the  carbonic  acid  which  is 
no  longer  eliminated  in  sufficient  quantity  through  the 
obstructed  air-passages. 

Finally,  there  is  a  third  cause  for  the  accumulation  of 
carbonic  acid  in  the  blood  :  the  accumulation  may  come 
about  through  excessive  production,  and  this  is  what 
occurs  in  violent  exercise. 

It  is  a  truth  demonstrated  by  physiology  that  the 
production  of  carbonic  acid  by  an  animal  increases  with 
increased  muscular  activity.  The  work  of  Sanson  has 
shown  that  in  large  animals,  such  as  the  horse  and  the 
ox,  the  quantity  of  carbonic  acid  given  out  by  the  lungs 
is  doubled  or  even  trebled  when  the  animal  is  performing 
violent  exercise,  such  as  running.* 

This  increase  in  the  production  of  carbonic  acid 
during  work  has  been  ascertained  in  all  animals,  even  in 
insects. 

A  bee-hive  contains  twenty-seven  times  as  much 
carbonic  acid  when  the  swarm  is  working  as  it  does 
when  the  latter  is  at  rest. 

*  Sanso7i.     La  Respiration  des  grands  animaux. 


80  PHYSIOLOGY  OF  BODILY  EXERCISE. 

Finally,  in  man,  in  a  given  time,  there  is  discharged 
by  respiration  : 

0'35  grammes  of  carbonic  acid  during  sleep  ; 
0"6o  „         „  „  „      while  sitting  ; 

I '65  „         „  „  „      while  running. 

Besides  the  increase  in  the  carbonic  acid  exhaled  by 
the  lungs,  there  has  also  been  determined  an  increase  in 
the  quantity  of  this  gas  eliminated  by  the  skin  during 
work.  Further,  in  spite  of  the  increased  elimination,  there 
remains  an  excess  in  the  system  for  a  certain  time  after 
the  exercise  is  over.  If  we  kill  an  animal  after  forced 
exercise,  we  find  much  more  carbonic  acid  in  the  muscles 
than  in  the  normal  condition,  and  the  arterial  blood  is 
blackish,  and  resembles  venous  blood  in  its  chemical 
composition. 

Thus,  when  a  man  performs  muscular  work,  an  excess 
of  carbonic  acid  is  produced  throughout  his  system.  A 
man  who  performs  a  very  violent  exercise  is  threatened 
with  asphyxia  just  as  much  as  an  animal  into  the  veins 
of  which  we  inject  carbonic  acid.  In  both  cases  the 
cause  of  the  respiratory  disturbance  is  the  same  :  there 
is  a  poisoning  of.  the  blood  by  the  same  toxic  substance  ; 
only,  in  the  man  rendered  breathless  by  muscular  work, 
the  poison  has  not  been  introduced  from  without,  it  has 
been  formed  within  the  system  itself  It  is  a  product  of 
dissimilation  which  has  accumulated  in  the  economy  in 
too  large  a  dose. 

The  presence  of  an  excess  of  carbonic  acid  in  the 
blood  produces  the  sensation  of  dyspnœa.  Dyspnœa, 
or  increased  respiratory  need,  produces,  in  a  reflex 
manner,  increased  respiratory  effort.  There  is  a  strife 
between  the  poisonous  substance  and  the  eliminating 
organs  whose  function  it  is  to  expel  it  from  the  system. 
For  a  longer  or  shorter  time,  according  to  the  respiratory 
fitness  of  the  individual,  the  increased  action  of  the  lung 
compensates  for  the  increased  production  of  carbonic 
acid,  and  the  distress  is  bearable.  But  if  the  work 
increases,  the  production  ends  by  exceeding  the  elimi- 
nating power  of  the  organs  ;  the  pulmonary  air-cells  are 


BREATHLESS  NESS.  8 1 

no  longer  able  to  discharge  all  the  carbonic  acid  brought 
to  them  by  the  blood,  and  this  gas  accumulates.  If  at 
this  moment  the  work  is  stopped,  the  production  of  the 
poisonous  gas  becomes  normal  in  quantity,  the  excess 
present  in  the  system  is  eliminated,  and  the  distress 
ceases.  If,  on  the  other  hand,  the  violent  exercise  is 
continued  without  a  break,  carbonic  acid  at  last  accumu- 
lates in  very  large  quantities,  and  may  finally  produce 
serious  accidents,  even  death  from  asphyxia. 

So  intimate  is  the  correlation  between  the  quantity 
of  work  performed  by  the  muscles,  the  quantity  of 
carbonic  acid  produced  in  the  system,  and  the  intensity 
of  the  respiratory  distress  experienced.  Muscular  work 
increases  the  quantity  of  carbonic  acid  in  the  blood,  and 
the  excess  of  this  gas  leads  to  an  increase  of  the  res- 
piratory need. 

This  is  the  explanation  of  the  law  which  is  deduced 
from  the  observation  of  phenomena,  and  which  we  here 
enunciate  : 

The  intensity  of  breathlessness  during  exercise  is  in 
direct  proportion  to  the  expenditure  of  force  donanded  by 
the  exercise  in  a  given  time. 

The  cause  of  breathlessness  is  a  kind  of  poisoning  of 
the  system  with  one  of  its  own  products  of  dissimilation, 
an  auto-intoxication  by  carbonic  acid.  The  excessive 
increase  of  the  respiratory  need,  and  the  exaggeration 
of  the  respiratory  movements  which  we  observe  in  a 
man  rendered  breathless  by  muscular  exercise,  are  due  to 
the  imminence  of  J:he  danger  of  intoxication,  and  to  the 
effort  made  by  the  organism  for  the  speedy  elimination 
of  the  poison. 

III. 

If  we  review  all  the  circumstances  in  which  breath- 
lessness is  produced,  we  shall  see  that  our  theory  gives 
a  satisfactory  explanation. 

For  the  production  of  breathlessness  it  is  necessary 
that  much  work   should   be  done  in  a  short  time,  that 


82  PHYSIOLOGY  OF   BODILY   EXERCISE. 

the  exercise  should  be  taken,  so  to  speak,  in  a  large 
dose,  so  that  the  increase  of  carbonic  acid  may  be  rapid 
enough  to  bring  about  an  excessive  accumulation  of 
this  gas,  and  the  saturation  of  the  blood  with  it. 

If  the  exercise,  for  instance,  merely  doubles  the  pro- 
duction of  carbonic  acid,  breathlessness  will  not  occur, 
for  the  elimination  of  this  gas,  according  to  the 
researches  of  Sanson,  may  be  trebled  during  work. 
The  respiration  will  be  rendered  more  active^  but  it 
will  not  be  insufficient.  If,  on  the  other  hand,  the 
muscular  work,  in  a  given  time,  produces  a  greater 
quantity  of  carbonic  acid  than  the  lungs  are  able  to 
eliminate  in  the  same  period,  this  gas  will  accumulate 
in  the  system  ;  the  respiratory  distress  will  increase 
every  moment,  and  will  finally  interrupt  the  work. 

Thus  are  explained  the  phenomena  by  which  we  are 
struck  while  practising  bodily  exercise,  and  which  show 
how  muscular  fatigue  is  produced  under  different  condi- 
tions to  breathlessness. 

The  quantity  of  carbonic  acid  produced  by  a  group 
of  muscles  in  a  given  time  is  in  proportion  to  the 
amount  of  work  they  do.  Further,  the  work  which  a 
group  of  muscles  is  able  to  do  without  fatigue  is  in  direct 
ratio  to  the  power,  that  is  to  the  number  and  size,  of  the 
muscles  forming  this  group.  If  then  an  exercise  is 
localised  in  a  very  small  group  of  muscles,  fatigue  will 
ensue  before  a  large  quantity  of  work  has  been  done,  and 
before  a  large  dose  of  carbonic  acid  has  been  poured 
into  the  blood.  The  eliminating  power  of  the  lungs 
will  exceed  the  power  for  work  of  the  active  muscles  : 
muscular  fatigue  will  precede  breathlessness.  If,  on  the 
other  hand,  the  muscles  put  in  action  are  very  numerous 
and  very  powerful,  they  will  be  able,  before  being 
fatigued,  to  perform  a  large  quantity  of  work,  and  con- 
sequently, to  produce  a  very  large  dose  of  carbonic  acid. 
Their  power  for  work  will  exceed  the  eliminating  power 
of  the  lungs.  Breathlessness  will  this  time  precede 
fatigue. 

This  is  why  exercises  performed  with  the  upper  limbs, 


BREATHLESSNESS.  83 

the  muscles  of  which  are  relatively  feeble,  mostly  cul- 
minate in  fatigue  without  producing  breathlessness. 
These  muscles  do  relatively  little  work  at  a  time  ;  they 
are  fatigued  before  they  have  produced  the  dose  of 
carbonic  acid  necessary  to  embarrass  the  lungs. 

The  lower  limbs,  on  the  contrary,  with  their  powerful 
muscular  masses,  can  perform  in  a  few  seconds  a  great 
deal  of  work,  and  throw  into  the  blood  a  great  quantity 
of  carbonic  acid.  So  w^hen  we  demand  from  them  all 
the  work  of  which  they  are  capable,  they  produce  in  a 
very  short  time  more  carbonic  acid  than  the  lungs  can 
eliminate,  Breathlessness  interrupts  the  exercise  while 
the  muscles  are  still  full  of  vigour. 

Breathlessness  occurs  w^henever  muscular  work  pro- 
duces, in  a  given  time,  more  carbonic  acid  in  the  blood 
than  the  lungs  can  eliminate  in  the  same  time. 

The  quantity  of  work  necessary  to  produce  breath- 
lessness should  not  then  be  the  same  in  all  persons,  for 
not  everyone  can  eliminate  by  the  lungs  the  same 
quantity  of  carbonic  acid  in  the  same  time.  We  may 
say  that  there  exists  for  each  individual  a  coefficient  of 
breathlessness  which  varies  with  his  respiratory  fitness. 
The  moment  when  breathlessness  will  occur  will  be 
retarded  by  the  vigour  of  the  subject,  the  size  of  his 
lungs,  the  perfect  integrity  of  his  heart,  and  above  all  by 
his  acquired  aptitude  in  the  use  of  his  respiratory  organs. 

But,  however  great  the  respiratory  powder  of  the  indivi- 
dual, if  we  suppose  an  exercise  as  violent  as  possible,  and 
one  which  brings  into  action  all  the  muscles  of  the  body 
at  once,  breathlessness  will  be  produced  almost  instanta- 
neously, because  the  muscular  system,  as  a  whole,  can 
produce  in  a  given  time  more  carbonic  acid  than  the 
lungs  can  eliminate. 

It  is  for  this  reason  that  it  is  important  in  an  exercise 
of  great  swiftness,  such  as  running,  not  to  make  at  the 
outset  all  the  efforts  of  which  we  are  capable,  but  to 
economise.  In  order  to  avoid  becoming  breathless 
during  the  exercise,  we  must  regulate  the  work  of  the 
muscles  by  the  eliminating  powder  of  the  lungs,  in  such  a 
manner  that  the  quantity  of  carbonic  acid  produced  in 


84  PHYSIOLOGY  OF  BODILY  EXERCISE. 

a  given  time  shall  not  be  greater  than  that  which  the 
respiratory  organs  can  dispose  of  in  the  same  time. 

The  habit  of  practising  an  exercise  or  of  performing  a 
work  brings  a  man  or  an  animal  instinctively  to  regulate 
the  intensity  of  his  muscular  effort  by  his  respiratory 
power,  in  such  a  manner  that  there  may  be  an  equili- 
brium between  the  amount  of  carbonic  acid  produced 
by  the  muscles  and  the  amount  eliminated  by  the  lungs. 
Thus  it  is  that  every  man,  every  animal,  comes  to  adopt 
in  the  exercise  of  running,  a  pace — or  rather  a  rate^ 
from  which  he  cannot  depart  under  pain  of  breathless- 
ness. 

In  horse  racing,  certain  animals  are  charged  with 
making  the  mnning.  They  force  themselves  to  the 
front  at  the  start,  endeavouring  to  lead  their  adversaries 
into  an  extremely  rapid  gallop.  The  aim  of  this 
manoeuvre  is  to  force  the  other  horses  to  exceed  their 
paces,  while  a  confederate  holds  himself  in  check  in 
order  to  take  the  lead  when  the  others  begin  to  be 
exhausted.  A  horse  which  exceeds  its  paces  is,  from 
the  physiological  point  of  view,  an  animal  which  pro- 
duces more  carbonic  acid  than  it  is  able  to  eliminate. 
This  causes  a  rapid  intoxication,  which  paralyses  its 
action.  To  win  the  race,  a  horse  is  almost  always 
obliged  to  provide  at  a  given  moment  all  the  swiftness 
of  which  its  legs  are  capable,  and  consequently,  to  exceed 
its  paces.  But  the  art  of  the  jockey  is  not  to  let  it  exceed 
its  paces  till  the  last  possible  moment,  so  that  it  may  not 
be  exposed  to  this  inevitable  intoxication  till  close  to  the 
goal. 

Nevertheless,  if  a  violent  exercise  is  performed  con- 
tinuously for  a  certain  time,  breathlessness  is  always 
produced  in  the  end,  although  the  individual  does  not 
exceed  his  paces.  Let  us  suppose  a  case  in  which  the 
muscular  work  produces  a  quantity  of  carbonic  acid 
just  equal  to  that  which  can  be  eliminated  by  the  lungs. 
At  first  there  will  be  no  breathlessness,  as  there  is  an 
equilibrium  between  production  and  elimination.  But 
if  the  work  goes  on,  respiration  in  the  end  becomes 
embarrassed.     Running  at  a  moderate  pace,  for  instance, 


BREATIILESSNESS.  $$ 

which  we  can  do  for  five  minutes  without  losing  breath, 
will  produce  breathlessness  in  a  quarter  of  an  hour, 
although  the  pace  remains  the  same. 

It  is  because,  the  quantity  of  work  remaining  the 
same,  the  respiratory  power  is  diminished  by  the  very 
continuance  of  the  exercise.  In  the  very  act  of  working 
disturbances  are  produced  in  the  functions  of  the  respi- 
ratory apparatus.  The  circulation  of  the  blood  through 
the  lungs  is  increased,  and  there  results  at  first  an  active 
congestion.  Later  however,  we  \i-àNÇi  passive  congestion 
as  a  result  of  fatigue,  of  th^  forcing  of  the  right  side  of 
the  heart,  the  contraction  of  which  is  not  sufficiently 
powerful  to  drive  the  blood  through  the  pulmonary  vessels. 
Further,  the  nerve-centres,  strongly  stimulated  by  the 
carbonic  acid  brought  to  them  by  the  blood,  react  on  the 
movements  of  the  lung  in  a  reflex  manner,  and  respira- 
tion becomes  short,  precipitate,  and  irregular. 

The  congestion  of  the  lungs,  the  derangement  of  the 
respiratory  movements,  the  excitement,  and  then  the 
enfeeblement  of  the  heart-beat,  are  so  many  secondary 
factors  of  breathlessness,  which  we  shall  study  in  the 
next  chapter.  The  part  they  play  in  the  production  of 
dyspnoea  in  the  course  of  exercise  is  important,  for  they 
create  obstacles  to  the  free  working  of  the  lungs  at  the 
moment  when  there  is  need  that  these  organs  should 
work  with  their  fullest  power. 


CHAPTER  in. 

BREATHLESSNESS — {conthiued). 

Mechanism  of  Breathlessness — Reflex  Disturbances  of  the  Res- 
piratory Movements — Physical  Sensations  and  Moral  Impres- 
sions —  Stainmeri7tg  Respiration  —  Why  we  become  less 
Breathless  at  a  Fencing- School  than  in  a  Duel — 'Reflexes  due 
to  Carbonic  Acid — Reflexes  are  at  first  Useful  ;  they  become 
Dangerous  when  Exaggerated — Dangers  of  Instinctive  Move- 
ments—  Fart  played  by  the  Heart  in  Breathlessness — Active 
Congestions — Fatigue  of  the  Heart-Muscle  and  Passive  Con- 
gestion of  the  Lungs — The  Influence  of  the  Heart  is  Secondary 
— Cessation  of  Breathlessness  notwithstanding  the  Persistence 
of  Circulatory  Disturbances  after  Exercise — Personal  Observa- 
tion ;  the  Ascent  of  Canigou — Effort;  its  part  in  Breathless- 
ness— Prompt  Advent  of  Breathlessness  in  Wrestling — Sprint 
Running  and  Long-Distance  Running — Our  observations  on 
the  Rhythm  of  Respiration  during  Breathlessness — Inequality 
of  Expiration  and  Inspiration  during  Breathlessness  ;  Causes 
of  this  Inequality — Serious  Phenomena  of  Breathlessness — 
Action  of  Carbonic  Acid  on  the  Muscular  Fibres  of  the  Heart. 

The  essential  condition  of  respiration  is  the  presence  in 
the  lungs  of  atmospheric  air  and  of  venous  blood,  in 
order  that  the  inspired  air  may  give  up  its  oxygen  to 
the  blood,  and  that  the  blood  may  rid  itself,  in  exchange, 
of  its  carbonic  acid.  It  is  evident  that  any  obstacle  to 
the  circulation  of  blood  in  the  pulmonary  capillaries  or 
to  the  free  entrance  of  air  into  the  pulmonary  air-cells, 
will  render  the  respiratory  act  incomplete. 

Now  violent  exercise  causes  a  disturbance  in  the 
respiratory  movements  which  renders  them  less  efficient 
in  drawing  air  into  the  chest,  at  the  same  time  as  it 
produces  in  the  vascular  system  disturbances  capable 
of  hindering  the  pulmonary  circulation. 

Each  of  these  two  effects  deserves  attentive  study. 


BREATIILESSNESS.  8/ 


ï. 


Exercise  may  have  a  direct  action  on  the  respiratory 
movements,  for  many  muscular  actions  are  performed 
with  the  aid  of  the  muscles  of  the  thorax  or  the  back. 
These  muscles,  being  used  in  the  work,  are  momentarily 
distracted  from  their  function  as  respiratory  muscles. 
They  can  even  stop  respiration  when  they  take  their 
fixed  point  at  the  ribs  for  the  purpose  of  moving  the 
upper  limbs.  Effort,  which  we  discussed  at  length  in 
the  chapter  on  Movements,  is  the  type  of  the  actions 
which  stop  respiration  by  fixing  the  thorax. 

This  action  has  important  consequences  on  the  cir- 
culation of  the  blood,  and  it  is  in  this  way  that  it 
especially  affects  the  respiratory  function.  But  it  also 
momentarily  hinders  the  interchange  of  gases,  and  this 
usually  at  a  time  when  it  is  most  needed.  Stoppage  of 
respiration  during  repose  has  no  grave  consequences, 
because  it  is  always  followed  by  a  compensatory  effect, 
by  a  series  of  longer  and  deeper  respirations,  which 
promptly  eliminate  the  carbonic  acid,  of  which  the 
quantity  retained  in  the  body  cannot  be  excessive  while 
the  muscles  are  at  rest.  But  if  the  effort  has  taken 
place  during  work,  it  happens  that  the  working  of  the 
lungs  is  hindered  just  at  the  moment  when  their  action 
ought  to  be  increased  ;  the  suspension  of  respiration  shuts 
the  passage  by  which  carbonic  acid  ought  to  be 
eliminated,  at  the  very  time  when  the  muscles  are 
producing  three  or  four  times  as  much  of  this  gas  as 
usual. 

Respiration,  which  hardly  answered  the  needs  of 
the  system  while  the  lungs  were  freely  performing  their 
work,  becomes  suddenly  insufficient  when  the  thoracic 
movements  are  so  hindered.  Thus  the  repeated  stoppage 
of  respiration  during  work  may  become  a  very  efficient 
cause  of  dyspnœa,  while  in  a  state  of  repose  it  produced 
but  a  passing  disturbance. 

But  effort,  and  the  other  muscular  actions  capable  of 
suspending  or  hindering  the  play  of  the  ribs,  are  not  the 


88  PHYSIOLOGY  OF   BODILY  EXERCISE. 

most  frequent  causes  of  the  respiratory  troubles  which 
we  observe  during"  exercise.  Respiration  is  often  pro- 
foundly modified  in  its  rhythm,  its  amplitude,  and  its 
frequency,  without  it  being  possible  for  us  to  consider 
these  disturbances  as  a  result  of  the  direct  action  of  the 
exercise  performed.  Very  often  we  see  that  exercises, 
whose  performance  does  not  involve  the  use  of  the 
thoracic  muscles,  nevertheless  profoundly  affect  the 
thoracic  movements. 

It  is  then  by  a  reflex  action  that  we  must  account  for 
this  indirect  effect  of  exercise. 

Reflex  actions,  capable  of  modifying  the  rhythm  of 
respiration,  have  very  various  origins,  and  the  lungs  are 
very  frequently  exposed  to  their  effects,  being  the  most 
impressionable  of  all  organs.  In  order  fully  to  under- 
stand the  reflex  effects  to  which  the  lungs  are  subject, 
we  must  recall  the  fact  that  powerful  impressions  in 
general,  whether  physical  or  moral,  tend  to  produce  in- 
voluntary movements,  and  that  these  movements  may 
take  place  just  as  much  in  the  muscles  of  organic  as  in 
those  of  animal  life. 

When  we  pass  near  a  room  in  which  a  person  is 
taking  a  cold  shower-bath  for  the  first  time,  we  hear 
sighs  and  suppressed  groans.  These  inarticulate  sounds, 
which  resemble  cries  of  distress,  are  simply  reflex 
actions.  The  sensation  of  cold  which  the  water  causes 
when  applied  to  the  chest-walls  is  transmitted  to  the 
nerve-centres  as  a  stimulus  w^hich  produces  abrupt 
expiratory  and  inspiratory  efforts.  The  air  is  violently 
drawn  into  the  chest,  or  driven  out  from  it  in  an 
irregular  manner,  and  causes  in  its  passage  vibrations  of 
the  vocal  cords  without  the  influence  of  the  will.  If 
the  impression  produced  by  the  cold  water  is  too  strong, 
the  reflex  action  may  culminate  in  a  complete  stoppage 
of  respiration  :  it  becomes  impossible  for  the  air  to 
enter  the  chest,  or,  having  entered,  to  get  out  again. 
Hence  there  is  a  kind  of  distress,  a  momentary  suffoca- 
tion which  makes  hydrotherapeutics  very  painful  at 
first  to  impressionable  patients. 

Every  violent  physical   sensation,  wherever  situated, 


BREATHLESSNESS.  i^g 

will  re-act  upon  the  lung  ;  every  powerful  moral  emotion, 
whatever  its  cause,  will  also  make  its  influence  felt  on 
the  respiratory  function.  Joy,  sorrow,  fear,  can  produce 
reflex  effects  on  the  respiratory  movements  which  we 
call  a  laugh,  a  sob,  a  sigh,  a  cry. 

Every  time  that  the  rhythm  of  respiration  is  disturbed, 
breathlessness  is  produced,  even  in  the  condition  of 
muscular  repose.  IMoreover,  very  often,  causes  of  a 
moral  order  come  to  increase  the  tendency  to  breath- 
lessness while  performing  an  exercise.  An  exercise 
which  is  performed  with  tranquil  breathing  if  the  mind 
is  free  from  care,  promptly  produces  respiratory  dis- 
turbances if  the  mind  is  brooding  and  pre-occupied. 

Those  who  have  acted  as  seconds  in  a  duel  to  men 
accustomed  to  the  use  of  the  sword,  know  that  they 
become  breathless  in  the  duel  much  more  quickly  than 
they  do  in  a  fencing  school.  Yet  their  movements  are 
more  prudent,  more  limited  ;  they  make  no  violent  attack, 
and  they  watch  more  than  move  ;  they  expend  less 
force,  but — their  rapiers  have  sharp  points. 

Depressing  emotions  make  their  effects  felt  on  the 
respiration  of  animals  as  well  as  of  man.  A  sensitive 
horse  which  is  badly  used  when  at  work,  or  even  roughly 
spoken  to,  quickly  becomes  breathless. 

For  the  same  reason,  wild  animals  can  be  caught,  when 
hunted,  by  domestic  animals,  in  spite  of  their  being 
more  accustomed  to  fatigue  ;  the  dog  is  incomparably 
less  swift  than  the  hare,  but  is  able  to  catch  it  :  the 
fright  of  the  hunted  animal  disturbs  its  breathing  and 
robs  it  of  much  of  its  strength 

Moral  impressions,  like  physical  sensations,  can  only 
lessen  the  respiratory  power  by  reflex  effects  which  dis- 
turb the  regular  working  of  the  pulmonary  air-current. 
Under  the  influence  of  fear  we  see  the  movements  of 
the  chest,  now  quickened  beyond  measure,  now  slackened, 
and  momentarily  stopped,  now  following  at  irregular 
intervals.  The  defect  of  co-ordination,  the  disorder  of 
the  respiratory  movements  which  w^e  observe  under  the 
influence  of  fright,  much  resembles  the  incoherence  in 
the  movements  of  the  lips  which  prevents  a  man,  deeply 


go  PHYSIOLOGY  OF  BODILY  EXERCISE. 

moved,  from  clearly  articulating  his  words.  It  is  thus 
that  depressing  emotions  can  bring  on  a  kind  of 
stammering  respiration. 

The  disorder  of  the  respiratory  movements  destroys 
the  regularity  of  the  gas  interchange  which  takes  place 
in  the  lungs  between  the  venous  blood  and  the  atmos- 
pheric air,  and  thus  profoundly  hinders  the  function  of 
aeration  of  the  blood.  When  the  respiration  is  irregular, 
the  carbonic  acid  produced  by  work  cannot  be  eliminated 
as  fast  as  it  is  formed,  and  oxygen  cannot  be  introduced 
in  proportion  to  the  needs  of  the  system  ;  hence  the 
respiratory  need  is  unsatisfied  and  breathlessness  comes 
on. 

Moral  impressions,  then,  add  their  influence  to  that  of 
work  in  the  production  of  breathlessness,  not  by  in- 
creasing the  production  of  carbonic  acid,  but  by  check- 
ing its  regular  elimination.  The  more  impressionable 
the  subject,  the  more  easily  do  emotions  influence  his 
respiratory  actions.  Hence  the  superiority  in  certain 
bodily  exercises  of  men  who  are  calm  and  masters  of 
themselves.  The  fear  of  being  beaten,  the  annoyance 
of  seeing  himself  passed  for  a  moment,  may  diminish 
the  respiratory  power  of  an  athlete,  otherwise  very 
vigorous,  but  too  impressionable,  and  make  him  lose  the 
prize  for  running  or  rowing. 

There  is  a  striking  resemblance  between  the  respiratory 
disturbances  due  to  a  violent  moral  impression,  and 
those  which  result  from  a  powerful  physical  sensation. 
The  analogy  is  just  as  striking  if  we  compare  the 
modifications  produced  by  a  very  strong  emotion  in  the 
working  of  the  lungs,  and  those  produced  by  too  violent 
an  exercise.  If  we  find  ourselves  before  a  man  panting 
from  terror,  we  might  fancy  he  was  out  of  breath  from 
fast  running.  In  both  cases  there  is  the  same  picture  : 
breathing  irregular,  speech  interrupted,  complexion  livid. 

In  a  man  overcome  by  a  powerful  physical  impression, 
such  as  a  cold  shower-bath,  in  a  man  carried  aiuay  by 
fear,  and  in  a  man  breathless  from  running,  there  is  a 
common  element  capable  of  disturbing  respiration  \  there 


BREATHLESSNESS.  QI 

ÎS  a  kind  of  shock  undergone  by  the  region  of  the  nerve- 
centres  which  presides  over  the  respiratory  movements. 
The  cold  shower-bath  influences  the  breathing  by  the 
powerful  sensation  which  the  nerves  of  the  skin  transmit 
to  the  brain.  Fear  acts  by  producing  a  commotion  in 
the  nerve-centres,  the  mechanism  of  which  we  do  not 
understand,  but  the  effects  of  which  are  analogous  to 
those  of  a  physical  impression.  As  for  muscular  work,  it 
makes  its  effect  felt  on  the  respiratory  centre  because  it 
profoundly  modifies  the  composition  of  the  blood  ;  there 
accumulates  in  this  liquid  an  excess  of  carbonic  acid,  and 
this  substance  has  the  property  of  acting  on  the  medulla 
oblongata,  from  which  the  respiratory  nerves  arise,  as  a 
stimulus  which  produces,  in  a  reflex  manner,  profound 
m.odifications  in  the  respiratory  movements. 

The  stimiulation  of  the  medulla  oblongata  by  the 
carbonic  acid  in  the  blood  is  not  perceived  as  clearly  as 
an  external  impression,  but  it  results  in  a  crude  sensa- 
tion, the  respiratory  need,  which  immediately  causes 
reflex  movements  in  the  respiratory  muscles.  These 
movements,  which  are  quite  automatic,  aim  at  elimina- 
ting from  the  system  with  greater  energy  the  carbonic 
acid  which  is  tending  to  accumulate  too  much  in  the 
system. 

II. 

It  is  a  physiological  law  that,  under  the  influence  of  an 
impression  announcing  a  danger,  the  organs  react,  and 
endeavour  to  remove  the  injurious  agent.  A  grain  of 
dust  introduced  into  the  eye  produces  a  reflex  winking, 
by  which  the  eyelids  seek,  as  it  were,  to  sweep  it  away  ; 
if  a  foreign  body  has  entered  the  air-passages,  it  excites 
coughing  ;  in  the  nostrils  it  is  driven  out  by  a  sneeze. 

All  these  are  reflex  actions,  and  it  is  by  a  similar 
reflex  action  that  carbonic  acid  in  excess  causes  an 
acceleration  of  the  respiratory  movements  for  its  elimina- 
tion. 

The  instinct  in  virtue  of  which  the  respiratory  move- 
ments are  modified  during  violent  exercise  is  then  so 
intimately  bound  up  with  the  preservation  of  the  indi- 


92  PPIYSIOLOGY  OF   BODILY  EXERCISE. 

vidual,  that  it  seems  astonishing  at  first  sight  that  it  can 
produce  ill  effects,  and  hinder  the  accomplishment  of  the 
functions  over  which  it  presides. 

It  is  because  instinct  is  a  blind  force  which  measures 
the  intensity  of  its  action  by  the  strength  of  the  stimulus 
received,  without  considering  the  result  produced.  We 
daily  see  the  most  serious  accidents  arise  from  an  ex- 
aggerated or  inopportune  exertion  of  the  automatic 
power  of  the  organs.  It  is  thus  that  the  peristaltic 
contractions  of  the  intestine,  which  are  useful  for  driving 
out  a  foreign  body,  or  the  undigested  residue  of  food,  can 
occasion  by  their  exaggeration  grave  maladies,  such  as 
intestinal  invagination.  Similarly  the  contraction  of  the 
orbicular  muscle  of  the  eyelids  can  aggravate  an  affec- 
tion of  the  eye  accompanied  hy  photophobia.  The  lower- 
ing of  the  eyelids,  when  the  eye  fears  the  light,  is  an 
instinctive,  and  at  first  useful  movement.  But  if  the 
photophobia  is  extreme,  an  exaggerated  effort  at  occlu- 
sion results  from  the  excessive  irritability  of  the  eye,  a 
spasm  which  may  go  so  far  as  to  turn  in  the  edges  of  the 
eyelids,  when  the  eyelashes  will  produce  a  painful  friction 
of  the  cornea. 

Similarly,  on  the  part  of  the  pulmonary  organs,  a 
moderate  increase  of  the  respiratory  stimulus  renders 
their  function  more  effective  and  favours  aeration  of  the 
blood  ;  the  movements  of  the  thorax  become  more  ex- 
tensive and  more  frequent  ;  they  introduce  more  air  into 
the  lungs,  and  eliminate  more  carbonic  acid  from  them. 
But  if  the  respiratory  nerve-centres  are  over-stimulated, 
if  the  respiratory  need  is  exaggerated,  the  movements 
become  excessively  frequent,  and  here  is  one  of  the  prime 
causes  in  rendering  their  action  inefficient.  In  fact  very 
clear  experiments  show  that  when  the  respiratory  move- 
ments exceed  a  certain  number  per  minute,  the  quantity 
of  carbonic  acid  eliminated  diminishes  in  proportion  as 
the  frequency  of  respiration  increases. 

If  the  respiration  is  only  moderately  quickened,  the 
number  of  the  movements  more  than  compensates  for  the 
diminished  amplitude  of  each,  and  a  man  breathing 
thirly   tin.cs  a  minute  will  in  the  end  eliminate  more 


BREATHLESSNESS.  93 

carbonic  acid  than  one  breathing  i6  per  minute.  But  if 
the  respiration  is  immoderately  quickened,  the  carbonic 
acid  has  no  longer  time  to  traverse  the  pulmonary  air- 
cells,  and  the  expiratory  movement  expels  the  air  which 
has  hardly  entered. 

Thus  the  reflex  action,  at  first  useful  because  it 
rendered  respiration  more  active  and  increased  its  effi- 
ciency, becomes  in  the  end  a  hindrance  to  the  regular 
accomplishment  of  this  function,  and  constitutes  a  danger 
to  the  system. 

By  practice  we  are  able  to  exercise  a  certain  domina- 
tion over  actions  not  ordinarily  under  the  control  of  the 
will.  By  means  of  sustained  and  persevering  efforts  a 
man  can  strive  victoriously  against  the  respiratory 
reflexes  which  urge  him  to  quicken  his  respiratory  move- 
ments beyond  measure.  This  is  the  secret  of  the  resist- 
ance to  breathlessness  which  professional  runners  acquire. 
They  learn  to  regulate  the  working  of  their  lungs  and  to 
prevent  them  from  yielding  to  the  species  of  madness 
under  the  empire  of  which  the  panting  breast  but  half 
finishes  the  respiraLory  movements. 

Certain  diseases  offer  us  a  curious  demonstration  of  the 
rule  we  are  able  to  acquire  over  movements  which  are 
usually  involuntary,  to  hold  them  in  check_and  to  regu- 
late them.  Asthmatic  patients  who  have  long  suffered 
from  dyspnoea  have  learned  to  resist  the  impulse  which 
urges  every  oppressed  man  to  quicken  his  respiratory 
movements.  They  slow  the  rhythm  of  respiration  and 
prolong  it  as  much  as  possible.  In  this  manner  they 
are  able  to  better  their  condition,  although  the  disease  is 
unaltered.  Persons  who  have  been  emphysematous  for 
some  years,  knozu  how  to  breathe  and  get  much  more 
good  out  of  their  bad  lungs  than  they  could  at  the  out- 
set of  their  disease,  ^y  slowing  their  respiration  they 
render  it  more  efficient. 

Muscular  exercise  which  quickens  the  respiratory 
movements  up  to  the  advent  of  breathlessness,  often  pro- 
duces, when  pushed  too  far,  excessive  slowing,  and  even 

momentary  cessation  of  these  movements. 

8 


94  PPIYSIOLOGY  OF  BODILY   EXERCISE. 

These  two  opposed  effects  are  alike  due  to  reflex 
actions  which  the  stimulation  of  the  nerve-centres  by 
carbonic  acid  produces.  In  fact  moderate  stimulation  of 
the  medulla  oblongata,  such  as  that  caused  by  a  small 
dose  of  carbonic  acid,  produces  quickening- of  the  respira- 
tion ;  a  very  strong  stimulation  on  the  other  hand,  such 
as  is  produced  by  a  powerful  dose  of  this  gas,  makes  the 
respiration  slow.  We  see  these  different  effects  manifested 
when  the  nerves  of  the  lungs  are  stimulated  in  any  way 
whatever.  If  in  an  animal  we  give  a  feeble  electric 
stimulus  to  ^^  pneumo -gastric,  which  innervates  the  lung, 
we  cause  quickening  of  respiration  ;  but  if  we  stimulate 
it  very  strongly,  we  cause  slowing,  and  even  complete 
arrest  of  the  respiratory  movements. 

In  the  most  advanced  stages  of  breathlessness,  when 
forced  exercise  has  caused  the  accumulation  in  the  blood 
of  excessive  doses  of  carbonic  acid,  we  see  no  longer 
quickened  respiration,  but  respiration  half-finished  inter- 
rupted by  periods  of  stoppage,  and  finally  complete 
arrest  of  the  movement  of  the  lungs. 

III. 

The  heart  and  the  lungs  have  a  very  intimate  functional 
connection,  and  it  is  rare  that  the  working  of  one  of  these 
organs  is  disturbed  without  the  other  being  also  affected. 

Now  one  of  the  first  effects  of  exercise  is  to  increase 
the  frequency  of  the  heart-beat,  and  consequently  to 
quicken  the  blood-current. 

The  quickening  of  the  blood-current  during  exercise 
is  the  result  of  two  causes,  one  of  which  acts  on  the 
systemic  and  the  other  on  the  pulmonary  circulation. 

The  peripheral  circulation  is  quickened,  as  we  have 
explained  in  the  first  part  of  this  volume,  on  account  of 
the  increased  flow  of  blood  to  the  working  ipuscle.  A 
more  rapid  current  is  drawn  towards  the  muscle-fibre, 
and  in  the  end  all  the  blood  participates  in  this  increased 
activity  ;  the  pulse  is  more  frequent  and  more  blood  is 
sent  into  the  arteries.  The  whole  vascular  system  is  thus 
traversed  by  a  greater  quantity  of  blood. 


BREATÎILESSNESS.  95 

The  lungs,  like  the  other  organs,  become  the  seat  of  a 
more  active  circulation,  owing  simply  to  the  increased 
frequency  of  the  pulse. 

But  there  is  another  cause  of  increased  flow  through 
the  pulmonary  capillaries  ;  this  is  the  increased  need  felt 
by  the  organism  for  the  aeration  of  the  blood  in 
which  the  carbonic  acid  has  increased  in  quantity  during 
work.  Through  a  reflex  mechanism  which  has  been 
already  described,  blood  overcharged  with  carbonic  acid 
is  driven  more  energetically  towards  the  organ  which 
will  free  it  from  this  gas. 

From  these  two  causes  there  results  an  unusually 
large  flow  of  blood,  an  active  congestion  of  the  lungs. 
What  are  the  consequences  of  this  ? 

The  space  occupied  by  the  blood  which  swells  up  the 
pulmonary  capillaries  is  no  longer  available  for  the  air 
in  the  air-cells.  The  respiratory  field  is  thus  rendered 
smaller.  The  lung  then  makes  an  effort  of  expansion, 
in  virtue  of  which  certain  air-cells  not  usually  in 
action,  but  collapsed  and  closed,  swell  up  with  air,  and 
supplement  the  deficiency  of  the  ordinary  respiratory 
field.  This  accessory  respiration  occurs  especially  in 
the  apices  of  the  lungs.  In  this  manner  there  is 
established,  for  a  certain  time,  an  equilibrium  between 
the  amount  of  blood  which  passes  through  the  lungs 
and  the  amount  of  air  which  enters  them  ;  respiration 
has  become  fuller  and  deeper  ;  it  is  more  active,  but  not 
insufficient.     Breathlessness  has  not  yet  come  on. 

But  an  important  factor  of  respiratory  distress  soon 
comes  into  play  ;  this  is  the  fall  of  blood  pressure  in  the 
arteries.  The  heart,  in  spite  of  the  increased  frequency 
of  its  beat,  does  not  give  to  the  blood  so  powerful  an 
impulse  as  in  ordinary  circumstances,  and  the  blood- 
pressure  falls.*  It  is  a  well-established  fact  that  the 
heart  contracts  with  less  force  during  muscular  work 
than  in  a  condition  of  repose.  In  compensation,  the 
frequency  of  its  beat  may  be  more  than  doubled,  so 
that  the  increased  number  of  the  movements  makes  up 

^  Marey,     La  Circulation  du  Sang. 


C6  rHYSIOLOGY  OF   BODILY  EXERCISE. 

for  their  diminished  energy,  and  the  work  done  is,  on 
the  whole,  increased. 

The  blood,  driven  forward  less  vigorously  by  the 
cardiac  piston,  circulates  less  easily  through  the  small 
capillaries  of  the  lungs  ;  its  current  is  slowed,  there  is  a 
kind  of  stagnation,  of  blood-stasis,  and  the  small 
pulmonary  vessels  become  over-distended.  There  is 
established  a  passive  congestion  of  the  lungs.  These, 
engorged  with  blood,  now  offer  too  confined  a  space  to 
the  inspired  air,  and  moreover,  offer  a  serious  hindrance 
to  the  blood  circulation.  The  venous  blood  can  no 
longer  reach  the  air-cells  in  order  to  get  rid  of  its 
carbonic  acid,  and  there  is  a  reflux  to  the  heart. 

Passive  congestion  of  the  lungs  is  one  of  the  most 
formidable  factors  of  respiratory  distress  during  exercise. 
Now  all  the  causes  which  diminish  the  force  with  which 
the  blood  is  driven  through  the  capillaries  will  favour 
the  occurrence  of  pulmonary  congestion  ;  hence  we 
notice  a  very  marked  liability  to  breathlessness  in 
persons  whose  heart  is  hindered  by  disease  of  the 
valvular  orifices,  or  by  diminished  power  in  the  heart 
muscle,  in  all  cases,  in  fact,  in  which  there  is  a  tendency 
to  enfeeblement  of  the  cardiac  contractions. 

Breathlessness  is  very  quickly  produced  in  persons 
who  are  much  enfeebled,  whose  muscular  system  has 
lost  all  vigour,  for  instance,  in  persons  who  have  just 
recovered  from  a  long  illness.  The  heart,  being  a 
muscle,  participates  in  the  general  want  of  tone,  and 
its  contractions  become  feeble  at  the  slightest  effort. 
Now,  as  soon  as  the  heart-beat  becomes  feeble,  the  lungs 
are  congested  and  breathlessness  comes  on. 

Such  is  the  part  played  by  the  heart  in  the  production 
of  breathlessness.  Notwithstanding  the  importance  of 
circulatory  disturbances  during  exercise,  such  disturb- 
ances are  not  the  prime  cause  of  the  dyspnoea.  They 
act  by  mechanically  aggravating  the  respiratory  distress 
through  making  the  functions  of  the  lungs  more  difficult 
of  execution,  but  acting  alone  they  do  not  necessarily 
produce  breathlessness. 

A  series  of  personal  observations  enables  us  to  affirm 


BREATHLESSNESS.  gj 

that  after  exercise  the  dyspnœa  disappears  very  rapidly, 
while  the  circulatory  disturbances  continue  for  a 
relatively  long  time.  The  figures  which  we  are  about 
to  give  prove  that  these  two  phenomena  are  to  some 
extent  independent  of  each  other. 

Last  July,  making  the  ascent  of  Mt.  Canigou,  we 
assured  ourselves,  by  making  observations  on  ourselves, 
and  on  two  guides,  that  after  violent  exercise  the  heart 
remained  disturbed  long  after  the  lungs.  We  have 
noted  side  by  side  the  respiration  and  the  pulse  at  three 
different  stages  of  the  ascent,  (i)  during  complete 
repose,  (2)  w^hile  going  up  the  last  slopes,  which  are 
nearly  pc^rpendicular,  (3)  after  we  had  been  five  minutes 
on  the  top. 

Pulse.  Respiration. 
Complete  repose.         .         ,          62,  14. 

Most  rapid  ascent        .         .         123.  30. 

Five  minutes  after  reaching 

the  top  .         .         .         117.  14. 

Thus  the  disturbances  of  the  heart  during  exercise 
are  not  the  prime  cause  of  breathlessness,  for  in  this 
observation  made  on  four  healthy  persons,  at  the  time 
when  the  pulse  rate  was  still  almost  double  the  normal, 
the  lungs  had  returned  to  their  ordinary  rhythm  and  all 
respiratory  distress  was  over. 

If  we  follow  out  our  examination  of  the  disturb- 
ances produced  in  the  circulation  by  excessive  muscular 
exercise,  we  shall  find  a  last  and  very  serious  cause  of 
dyspnoea  through  diminished  action  of  the  heart  ;  this 
is  the  influence  of  the  blood  surcharged  with  carbonic 
acid,  on  the  heart-muscle  itself 

W^e  know  that  carbonic  acid  has  a  weakening  influence 
on  muscular  fibre  ;  if  we  inject  carbonic  acid  into  a 
muscle,  we  paralyse  it.  If  the  blood  in  the  cavities  of 
the  heart  is  changed  in  its  composition  and  contains 
an  excessive  quantity  of  this  acid,  it  exercises  on  the 
walls  of  the  heart  an  action  which  makes  them  lose 
their  energy.     Inertia  of  the  heart-muscle  will  add  to 


93  PHYSIOLOGY  OF  BODILY  EXERCISE. 

the  other  causes  of  the  slowing  of  the    blood-current, 
and  a  definite  stoppage  of  circulation  will  soon  occur. 

In  fact  the  stoppage  of  the  heart  is  the  last  of  the 
series  of  phenomena  of  asphyxia,  of  which  breathless- 
ness  pushed  to  its  furthest  limits  is  merely  a  particular 
foi  m. 

IV. 

To  sum  up,  most  of  the  causes  capable  of  rendering 
the  work  of  the  lungs  less  efficient,  end  in  passive  con- 
gestion of  the  lungs,  by  slowing  the  current  in  the 
capillaries.  Under  the  influence  of  this  blood-stasis, 
the  vessels  become  engorged,  the  air-cells  are  en- 
croached upon,  and  the  respiratory  field  is  diminished. 

Passive  congestion  of  the  lungs  is  only  produced  in 
an  advanced  stage  of  breathlessness,  and  when  it  occurs; 
it  produces  very  interesting  changes  in  the  rhythm  of 
respiration,  which  seem  up  to  the  present  time  to  have 
escaped  notice. 

When  a  man  has  carried  an  exercise  to  the  last 
degree  which  his  respiratory  power  enables  him  to 
reach,  his  respiration,  which  at  first  was  simply  quick- 
ened, comes  to  present  a  very  characteristic  type,  of 
which  we  will  give  an  exact  description  and  try  to  find 
a  physiological  explanation. 

In  a  state  of  repose,  the  two  times  of  respiration  are 
exactly  equal  ;  but  when  we  observe  a  runner  at  the 
moment  when  he  is  about  to  stop  for  want  of  breath, 
we  notice  that  his  respiratory  rhythm  has  completely 
changed.  Inspiration  is  much  longer  than  expiration. 
If  he  forces  himself  to  slow  his  respiration,  he  can  con- 
siderably prolong  the  period  of  inspiration,  but  finds  it 
quite  impossible  to  prolong  that  of  expiration.  An  in- 
voluntary inspiration  draws  more  air  into  the  chest 
before  the  latter  has  had  time  to  empty  itself.  A  man 
who  notices  his  own  sensations  during  an  exercise 
which  causes  breathlessness,  will  have  a  feeling  that 
he  cannot  entirely  empty  his  lungs.  When  he  has 
driven  out  a  small  quantity  of  air  he  has  an  unconquer- 
able need  for  a  fresh  inspiration.     If  he  tries  to  resist 


BREATHLESSNESS.  99 

this  need,  he  finds  it  as  difficult  as  it  is  to  check  a 
hiccough  :  it  is  an  irresistible  movement. 

We  will  describe  a  very  simple  experiment  which  has 
enabled  us  to  establish  the  very  peculiar  character  of  the 
respiration  of  a  breathless  man. 

Running  at  a  regular  pace  along  a  road,  and  carefully 
making  steps  of  equal  length  and  rhythm,  we  began  an 
inspiration  and  counted  the  number  of  steps  while  it 
lasted,  up  to  the  moment  when  the  need  for  expiration 
became  very  imperious.  Then  making  as  slow  an  ex- 
piration as  possible  we  again  counted  our  steps  until 
irresistibly  forced  to  make  a  new  inspiration.  The  steps 
were  practically  equal,  and  their  duration  may  serve  as  a 
unit  of  time.  Now  we  made  thirteen  steps  during  the 
period  of  inspiration,  and  only  five  during  the  period  of 
expiration. 

Such  is,  according  to  our  observations,  the  character 
of  respiration  during  running.  Inspiration  is  easy, 
deep,  and  unhindered  :  expiration  on  the  contrary,  is 
short,  insufficient,  interrupted  by  an  involuntary  in- 
spiratory movement,  and  leaves  the  sensation  of  an 
unsatisfied  need. 

This  change  in  the  rhythm  of  respiration  is  not  due 
to  the  mechanism  itself  of  running,  nor  to  the  attitude 
of  the  body  during  this  exercise,  for  when  we  have 
stopped  running  we  continue  for  some  minutes  to  make 
expirations  which  are  snorter  than  the  inspirations  which 
precede  them.  Moreover  we  have  satisfied  ourselves,  by 
varying  the  experiments,  that  all  exercises  which  cause 
breathlessness,  whatsoever  form  they  take,  produce  this 
defective  balance  between  the  two  times  of  respiration. 
In  fencing,  in  rowing  quickly,  in  dumb-bell  exercise,  we 
become  breathless  just  as  in  running,  and  we  observe 
the  same  inequality  in  the  two  periods  of  respiration. 

It  is  curious  to  note  that  the  respiration  of  persons 
suffering  from  asthma  has  a  type  the  exact  opposite  of 
that  we  have  just  described.  During  the  crisis  inspira- 
tion is  very  short,  and  expiration  lasts  twice  as  long. 

We  do  not  believe  that  anyone  has  hitherto  pointed 
out  the  change  of  which  we  are  speaking,  and  which  we 


100  PHYSIOLOGY  OF   LODILY   EXERCISE. 

may  consider  as  typical  of  the  dyspnœa  due  to 
muscular  exercise. 

The  following  is  our  explanation. 

The  first  result  of  violent  exercise  is  the  quickcnin^^ 
of  the  blood-current,  and  consequently,  as  we  explained 
in  Chapter  III.,  active  congestion  of  the  lungs.  In 
these  exercises  the  lungs  are  very  quickly  engorged  with 
blood,  and  there  is  great  need  for  their  disembarrassment 
by  increasing  the  activity  of  the  blood-current.  The 
movement  of  inspiration  increases  the  velocity  of  the 
current  by  a  force  of  aspiration  which  tends  to  empty 
the  overfilled  capillaries.  This  aspiration  lasts  as  long 
as  the  enlargement  of  the  thorax  continues  ;  hence  this 
movement  is  an  assistance  to  the  breathless  man  ;  on 
the  other  hand,  as  the  thorax  is  diminishing  in  size 
during  the  expiratory  movement,  the  blood-current  be- 
comes slo\yer  and  the  lungs  more  engorged.  Hence  the 
discomfort,  and  the  irresistible  impulse  to  a  prompt 
repetition  of  the  inspiratory  movement. 

We  may  say  that  the  lungs  of  the  breathless  man  are 
placed  between  two  different  needs.  On  the  one  hand 
they  have  to  drive  out  carbonic  acid  and  the  other 
products  of  dissimilation,  and  for  this  a  long  expiration 
would  be  necessary  ;  but  on  the  other  hand,  they  have 
to  free  themselves  from  vascular  engorgement,  and  there- 
fore expiration  is  cut  short  to  return  to  inspiration  which 
helps  the  circulation  through  the  lungs. 

In  order  to  observe  the  breathless  type  of  respiration, 
the  exercise  must  be  pushed  very  far,  for  the  character- 
istic change  we  have  described  only  precedes  by  very 
little  the  moment  when  work  becomes  impossible.  'At 
the  time  when  it  occurs  the  production  of  carbonic  acid 
is  no  longer  in  equilibrium  with  the  eliminating  power 
of  the  lungs,  and  the  respiratory  distress  tends  to  become 
a  serious  danger. 

V. 

There  is  a  phenomenon  in  muscular  exercise  the 
frequent  occurrence  of  which  very  quickly  causes  breath- 
lessness  :  this  is  effort. 


BREATIiLCSSNESS.  lOI 

Effort  brings  about  a  momentary  stoppage  of  respira- 
tion, and  in  this  already  we  have  a  hindrance  to  the 
functions  of  the  lungs.  But  there  is  further  an  action  on 
the  heart  and  great  vessels,  through  the  necessity  put 
en  the  thoracic  organs  to  serve  as  points  of  support  for 
the  ribs.  To  the  ribs  in  fact  are  attached  the  powerful 
muscles  which  fix  the  thorax  during  the  execution  of 
movements  demanding  a  great  expenditure  of  force. 
The  lungs,  inflated  by  a  forced  inspiration,  act  as  a  kind 
of  cushion  on  which  the  ribs  press,  and  this  pressure  is 
transmitted  to  the  great  thoracic  vessels  and  to  the  heart 
itself. 

It  is  easy  to  understand  the  fatigue  of  the  heart- 
muscle  and  of  the  contractile  walls  of  the  blood  vessels 
which  must  result  from  this  mechanical  action  which 
quickly  and  excessively  increases  the  tension  in  the 
vascular  system. 

Every  exercise  which  demands  a  series  of  efforts,  re- 
peated at  short  intervals,  very  quickly  induces  fatigue  of 
the  heart,  and  diminution  of  the  contractile  force  of  the 
blood-vessels.  There  results  a  transient  condition  of 
asystole,  and  the  subject  is  for  some  minutes  in  the  con- 
dition of  a  person  suffering  from  cardiac  disease. 
Breathlessness  is  thus  produced  by  a  kind  of  over- 
driving of  the  heart,  and  by  the  passive  congestion  of 
the  lungs  which  this  immediately  produces. 

On  performing  an  exercise  needing  very  prolonged 
efforts,  breathlessness  comes  on  with  astonishing  quick- 
ness. 

Two  wTestlers  who  strain,  each  trying  to  throw  the 
other,  remain  for  a  few  seconds  completely  motionless 
owing  to  the  resultant  of  their  several  efforts  w^hich 
balance  each  other,  then  suddenly  one  of  them  gives 
way  and  yields  to  the  pressure  of  the  other.  It  has 
hardly  taken  half-a-minute,  but  the  two  champions  are 
pale,  breathless,  and  unable  to  speak.  For  some  seconds 
it  seems  as  if  the  air  can  no  longer  enter  their  chests. 
Under  the  great  pressure  occasioned  by  their  athletic 
effort  the  larger  vessels  have  been  distended  until  they 
have   momentarily  lost  power  of  recoil,  the  heart  has 


102  PHYSIOLOGY  OF   BODILY  EXERCISE. 

been  compressed  till  it  is  on  the  point  of  ceasing-  to 
beat,  and  the  lungs,  engorged  with  blood  which  is  no 
longer  driven  forward,  remain  for  a  moment  under  the 
power  of  passive  congestion,  which  renders  them  unable 
to  work. 

Effort  plays  an  important  part  in  all  movements 
which  are  executed  with  a  person's  whole  force.  We 
must  often  attribute  effort  rather  to  the  energy  which  a 
man  throws  into  an  exercise  than  to  the  mechanism  of 
the  exercise.  Thus  long-distance  running  does  not  need 
the  production  of  effort,  while  this  action  occurs  during 
sprint  running.  Hence  the  latter  can  only  be  continued 
for  a  very  short  time  without  producing  breathlessness. 


CHAPTER  IV. 

BREATHLESSNESS — {conchlded). 

Three  Stages  of  Breathlessness— First  or  Salutary  Stage;  Respira- 
tion more  Active  but  not  Insufficient — Second  Stage — Symptoms 
of  slight  Carbonic  Acid  Intoxication;  Lead'^n  Complexion; 
Breathless  Respiration;  General  Discomforts — 1  nird  or  Asphyxiai 
Stage — Cerebral  Disturbances;  Symptoms  of  severe  Carbonic 
Acid  Intoxication;  Vertigo;  Unconscious  Movements;  Syncope; 
Stoppage  of  the  Heart — Observations — Dangers  ol  Running  as 
a  Sport — Too  vigorous  an  Assault-at-Arms — Animals  succumb- 
ing to  Breathlessness;  the  Horse  ridden  to  Death — Death  of  a 
Carrier  Pigeon — A  Hunted  Beast  which  Breaks  Cover. 

We  now  know  the  influence  of  muscular  exercise  on  the 
chemical  and  mechanical  phenomena  of  respiration,  and 
we  have  studied  the  effects  of  work  on  the  circulation  of 
the  blood  and  the  movements  of  the  heart.  We  have 
thus  brought  together  all  the  materials  which  are  neces- 
sary for  establishing  the  physiology  of  the  very  complex 
general  state  called  breathlessness,  and  we  may  sum  up 
its  principal  features. 

The  prime  cause  of  breathlessness  during  exercise,  is 
the  excessive  production  of  carbonic  acid. 

The  accessory  causes  are  :  (i)  the  disturbances  of  the 
respiratory  movements  produced  hy  muscular  exercise, 
(2)  the  disturbances  in  the  circulation  of  the  blood,  and 
the  congestion  of  the  lungs  which  these  cause. 

We  have  seen  how  an  excess  of  carbonic  acid  is  pro- 
duced by  the  combustions  which  occur  during  muscular 
work.  We  have  seen  how  everything  concurs  in  favour- 
ing its  accumulation.  We  have  before  us  an  organism 
striving  against  a  cause  of  disorganisation.  It  remain? 
for  us  to  examine  the  various  incidents  in  this  combat, 
the  manner  in  which  the  organism  defends  itself,  the 
conditions  in  which  it  has  the  upper  hand,  and  the  con- 
ditions in  which  it  may  succumb. 


104  PHYSIOLOGY  OF  BODILY  EXERCISE. 

I. 

We  may  group  in  three  stages  the  symptoms  pre- 
sented by  a  man  whose  respiration  is  under  the  influence 
of  violent  exercise. 

In  the  first  stage,  the  respiratory  movements  are  in- 
creased in  frequency  and  in  extent.  The  production  of 
carbonic  acid  is  increased,  but  the  respiratory  energy 
being  greater,  there  is  an  equilibrium  between  the  needs 
of  the  organism  which  demands  a  more  active  elimina- 
tion of  this  gas,  and  the  working  of  the  lungs  which  is 
powerful  enough  to  satisfy  these  needs.  During  a  time, 
which  varies  much  with  the  individual,  with  his  constitu- 
tion, with  his  resistance  to  fatigue,  and  above  all  with 
his  power  of  directing  his  respiration,  gained  from  his 
respiratory  education,  these  are  only  symptoms  of  greater 
vital  activity,  and  there  are  as  yet  no  signs  of  functional 
disturbance,  no  sensation  which  rises  to  the  degree  of  dis- 
comfort. The  man  has  a  general  sensation  of  warmth, 
some  throbbing  of  the  temples,  and  has  an  animated 
appearance,  flushed,  his  eyes  sparkling,  and  a  general 
aspect  of  cheerfulness  due  to  the  greater  activity  of  the 
circulation  and  the  resulting  active  congestions.  In  a 
word  it  is  the  stage  in  which  exercise  causes  a  greater 
intensity  of  life,  without  reaching  the  degree  of  dis- 
comfort or  of  danger. 

Here  we  have  the  really  salutary  dose  of  exercise,  the 
limits  within  which  we  must  keep  in  order  that  work 
may  cause  us  no  inconvenience.  But  nothing  varies 
more  with  the  individual  than  the  duration  of  this  in- 
offensive period,  which  is,  in  a  sense,  the  preface  of 
breathlessness.  In  some  persons  it  is  as  long  as  an 
hour  ;  in  others  the  stage  in  which  discomfort  begins 
is  reached  in  a  few  seconds. 

If  violent  exercise  is  prolonged,  the  equilibrium  is 
soon  broken  between  the  production  of  carbonic  acid, 
which  becomes  more  and  more  abundant,  and  the 
eliminating  power  of  the  lungs  which  is  insufficient  to 
free  the  organism  from  it     Respiratory  distress  occurs. 

In  the  second  period^  the  effects  of  insufficient  respira- 


BREATHLESSNESS.  I05 

tion  begin  to  show  themselves,  a  vague  discomfort  is 
experienced,  which  is  most  accentuated  in  the  pra^cor- 
dial  region,  but  which  is  rapidly  generalised  throughout 
the  body  and  notably  affects  the  head.  In  the  chest 
there  is  a  feeling  as  if  it  were  oppressed  by  a  weight,  or 
bound  down  by  a  girdle,  of  insufficient  air.  In  the  head 
there  are  clouds  obscuring  sight,  sparks  before  the  eyes, 
then  murmurs  and  ringing  in  the  ears,  and  finally  a 
certain  bluntness  of  sensation,  a  certain  confusion  in  im- 
pressions and  in  ideas.  All  these  disturbances  are  due 
to  the  action  upon  the  nerve-centres  of  an  excess  of  car- 
bonic acid.    They  indicate  the  beginning  of  intoxication. 

In  the  face  remarkable  changes  are  to  be  noticed, 
which  are  the  consequences  of  the  respiratory  distress 
and  of  the  efforts  made  to  draw  a  greater  quantity  of 
air  into  the  chest.  The  nostrils  are  dilated,  the  mouth 
and  eyes  widely  opened.  They  all  seem  to  be  widely 
opened  to  favour  the  entrance  of  the  air  which  the  lungs 
so  greatly  need. 

In  certain  animals  the  movements  associated  with 
respiratory  effort  are  especially  noticeable  in  the  nostrils. 
A  horse  returning  to  its  stable  after  a  race  is  typically 
breathless,  and  we  can  study  in  it  the  to-and-fro  move- 
ment of  the  nostrils  which  accompanies  the  movement  of 
the  flanks. 

The  alternating  movements  of  elevation  and  depression 
of  the  alae  nasi  have  for  their  object  the  presentment  of 
a  large  passage  to  the  air  drawn  into  the  chest.  They 
tend  to  occur  in  every  animal  with  increased  respiratory 
need.  When  we  look  at  a  small  child  suffering  from 
acute  bronchitis  or  pneumonia,  we  see  a  very  character- 
istic working  of  the  nostrils,  which  at  once  makes  the 
doctor  think  of  a  disease  of  the  respiratory  organs. 

The  colour  of  a  breathless  man  shows  very  striking 
modifications.  At  the  beginning  of  exercise  we  have 
said  that  there  is  animation,  more  colour  in  the  face,  due 
to  active  congestion.  But  in  the  second  period  the 
picture  has  changed.  To  the  lively  red  colour  has  suc- 
ceeded a  pale  and  wan  tint.  There  is  something  peculiar 
about  this  pallor  ;  it  is  not  uniform.     Certain   parts  of 


I06  PHYSIOLOGY  OF   BODILY   EXERCISE. 

the  face,  such  as  the  lips  and  the  cheeks,  have  a  violet- 
blackish  appearance  ;  the  rest  of  the  face  is  white  and 
colourless.  From  the  two  colours,  one  darker  and  the 
other  lighter,  there  results  a  grey,  leaden,  livid  appearance. 

The  following  is  the  explanation  of  the  different  colour 
of  different  parts  of  the  face.  The  violet  tint  is  due  to 
the  retention  of  blood  in  the  capillaries  which  are  losing 
their  elasticity,  and  in  which  the  circulation  is  failing. 
This  blood,  overcharged  with  carbonic  acid,  has  lost  its 
bright  red  colour,  hence  in  the  lips  and  other  more 
transparent  parts  of  the  face,  we  see  no  longer  the 
ordinary  red  colour  ;  they  have  the  blackish  colour 
characteristic  of  venous  blood. 

As  for  the  pallor,  this  is  due  to  a  transient  anaemia,  to 
the  emptying  of  the  arterioles.  The  heart,  the  energy 
of  which  diminishes  in  proportion  to  the  increase  of  the 
breathlessness,  does  not  send  forward  a  sufficient  quan- 
tity of  blood,  and  it  is  easy  to  understand  that  a  part 
receiving  less  blood  is  less  deeply  coloured  than  usual. 

The  leaden  hue  of  the  face  in  a  breathless  man  indi- 
cates an  already  profound  disturbance  of  the  system.  In 
no  case  should  exercise  be  continued  after  it  comes  on, 
for  it  indicates  the  beginning  of  asphyxia. 

It  is  at  this  stage  of  breathlessness  that  we  observe  the 
very  characteristic  change  in  the  rhythm  of  respiration 
which  we  described  in  the  last  chapter.  The  ordinary 
rhythm  is  lost  and  the  two  periods  of  respiration  become 
unequal.  The  first  period  increases,  and  the  second 
diminishes  ;  inspiration  becomes  three  times  as  long  as 
expiration.  This  change  in  the  rhythm  of  respiration  is 
an  indication  of  blood-stasis  in  the  capillaries  of  the 
lungs.  As  soon  as  it  occurs  we  can  see  that  the  organism, 
its  force  exhausted,  can  no  longer  fight  to  good  purpose 
against  the  poisonous  substance  which  permeates  it. 
The  congested  lungs  eliminate  less  carbonic  acid  than  i^ 
formed  by  the  muscles  at  work.  Intoxication  is  imminent. 

If  exercise  is  continued,  the  gravity  of  the  condition 
rapidly  increases.  We  may  call  the  asphyxiai  stage  the 
third  phase  of  breathlessness  into  which  the  organism 
passes  under  the  influence  of  forced  exercise. 


BREATIILESSNESS.  lo; 

This  third  stage  is  as  follows.  To  the  respiratory  dis- 
tress succeeds  a  sensation  of  anguish  generalised  through- 
out the  organism.  The  head  feels  as  if  bound  by  an 
iron  band.  Vertigo  is  very  distressing.  All  sensations 
become  more  vague  ;  the  brain  is  overcome  by  a  kind  of 
drunkenness.  The  subject  begins  to  become  unconscious 
of  what  is  passing,  his  muscles  continue  to  work  mechani- 
cally for  a  time,  then  they  stop,  and  the  man  falls  in  a  faint. 

At  this  time  respiration  is  of  a  different  type  to  that 
of  the  last  stage  ;  the  two  periods  are  both  short,  jerky, 
occasionally  interrupted  ;  with  them  are  mingled  swallow- 
ing movements  and  hiccough.  The  heart-beat  is  feeble 
and  intermittent.  The  pulse  is  small,  irregular,  and 
imperceptible.  When  exercise  is  continued  to  these 
extreme  limits  it  is  almost  always  stopped  by  grave  syn- 
cope, and  unless  prompt  help  be  given  the  syncope  may 
be  fatal. 

II. 

The  description  of  breathlessness  which  w^e  have  given 
is  no  picture  of  the  imagination.  We  have  studied  some 
of  the  phenomena  on  our  own  person  and  on  that  of  a 
friend  w^ho  has  willingly  helped  us  in  our  researches.* 

As  to  the  more  serious  phenomena,  they  are  often 
observed  in  England,  the  country  of  sport.  It  is  by 
no  means  rare  to  see  a  severe  fainting  fit  interrupt 
a  runner  in  his  course.  Often  a  match  between  two 
pedestrians  ends  before  either  has  reached  the  goal. 
One  of  the  champions,  breathless  to  the  last  degree, 
falls  unconscious,  and  is  only  restored  to  life  by  the 
cordials  and  rubbings  of  his  attendants.  Often  the  un- 
fortunate breathless  man  comes  to  himself,  and  after 
eliminating  some  puffs  of  the  carbonic  acid  which  is 
stifling  him,  wishes  to  continue  the  contest,  but  his 
muscles  are  impregnated  with  this  gas,  a  poison  which 
deprives  them  of  all  energy.  The  heart  itself,  bathed  in 
blood  overcharged  with  this  poisonous  product,  loses 
power  :  the  heart-muscle  is  paralysed  and  the  circulation 

*  This  friend  was  M.  A.  du  Mazaubrun  of  Limoges  ;  we  take 
this  opportunity  of  thanking  him  for  his  intelligent  assistance. 


I08  PHYSIOLOGY  OF   BODILY  EXERCISE. 

stopped.  The  case  is  then  unusually  grave,  and  the  most 
energetic  measures  have  sometimes  to  be  employed  to 
restore  to  life  the  man  who  has  overstepped  the  limits  of 
prudence. 

One  of  our  friends  who  was  somewhat  enfeebled  by 
excessive  intellectual  labours  wished  to  resume  bodily 
exercises  which  he  had  long  discontinued,  and  returned 
f)  the  fencing-school.  He  was  an  excellent  fencer,  and 
when  he  had  the  foil  in  his  hand  he  forgot  his  exhaustion 
and  only  thought  of  regaining  his  quickness  of  attack, 
and  his  energy  of  thrust.  After  ten  minutes  he  became 
very  breathless,  but  he  would  not  stop.  All  at  once  he 
fell  down  insensible,  his  face  pale,  his  forehead  covered 
with  a  cold  sweat  ;  his  breathing  and  pulse  had  stopped. 
We  at  once  went  to  his  assistance,  and  thanks  to  the 
horizontal  position  in  which  we  kept  him,  and  to  vigorous 
flicking  of  the  chest  and  temples  with  a  wet  towel,  his 
heart  began  to  beat  again  and  consciousness  returned. 

It  was  a  syncope  produced  by  breathlessness,  the 
occurrence  of  which  was  favoured  by  the  feebleness  of 
the  patient. 

Syncope  is  a  frequent  termination  of  breathlessness, 
just  as  of  asphyxia,  of  which  breathlessness  is  in  reality 
only  a  peculiar  form. 

Such  are  the  symptoms  and  course  of  respiratory 
fatigue,  and  such  are  the  dangers  to  which  a  person 
fighting  against  breathlessness  is  exposed. 

Breathlessness  is  a  ne  plus  ultra  imposed  upon  us  by 
the  instinct  of  self-preservation.  The  severe  suffering 
which  accompanies  it  is  a  true  cry  of  distress  on  the  part 
of  the  organism  to  which  the  consciousness  cannot  shut 
its  ears  with  impunity. 

Animals  which  are  overdriven  usually  succumb  to 
breathlessness.  The  horse,  which  as  Buffon  said,  "  dies 
for  better  obedience,"  gives  us  the  most  frequent  oppoi- 
tunity  of  studying  the  mode  of  death  of  which  we  are 
speaking.  It  is  common  enough  to  see  a  horse  fall  dead 
beneath  its  rider.  When  respiration  is  failing,  and  it 
wishes  to  pause  to  recover  breath,  it  is  answered   with 


BREATHLESS  NESS.  IO9 

whip  and  spur,  and  continues  to  gallop.  But  the  moment 
comes  when  the  dose  of  carbonic  acid  which  has  accu- 
mulated in  the  organism,  owing  to  the  insensate  speed 
demanded  of  it,  becomes  fatal,  and  the  animal  drops 
down  dead  from  asphyxia. 

Most  of  the  animals  which  die  suddenly  during  too 
violent  work  succumb  to  breathlessness.  It  is  a  common 
accident  with  all  animals  from  which  great  swiftness  is 
demanded,  and  the  very  birds,  so  well  made  for  speed, 
may  become  its  victims. 

We  saw  a  curious  instance  of  death  from  breathless- 
ness in  a  carrier-pigeon. 

Carrier-pigeons  undergo  a  special  training,  which  con- 
sists in  setting  them  free  at  points  continually  more  and 
more  remote  from  their  home.  The  bird  is  driven  by  its 
instinct  to  return  to  its  usual  home,  and  whether  it  be 
from  haste  to  reach  the  pigeon-house,  or  whether  it  be 
from  a  spirit  of  emulation,  it  seems  to  fly  home  as  swiftly 
as  it  possibly  can. 

A  friend  of  ours  had  a  pigeon,  which  was  the  swiftest 
in  the  district,  and  which  had  never  been  beaten  in  a 
race.  One  day  its  master,  who  lived  at  Limoges,  had 
sent  it  to  Bayonne,  where  it  was  to  be  set  free,  and  we 
were  awaiting  its  return,  well  knowing  that  it  would 
soon  traverse  the  375  m.iles.  This  time  its  speed  ex- 
ceeded our  expectation,  and  seven  hours  after  the  time  at 
which  it  was  set  free  the  valiant  little  bird  appeared  ;  we 
gave  a  cry  of  admiration,  but  the  poor  pigeon  paid  for  its 
glorious  prowess  with  its  life.  Just  when  it  was  about  to 
settle  on  the  pigeon-house  we  saw  it  flap  its  wings,  turn, 
and  fall  helpless  on  the  roof,  where  it  was  dashed  to  pieces. 

The  poor  pigeon  had  exceeded  the  measure  of  its 
strength  :  it  died  of  breathlessness  from  having  flown 
too  quickly.* 

*  We  sometimes  see  fatigued  quails  fall  on  ships.  We  have 
even  seen  them  fall  on  houses  or  in  the  streets.  In  these  rases 
the  bird  is  suffering  from  muscular  fatigue,  which  is  a  much  less 
serious  condition  than  breathlessness.  Quails  which  are  thus 
caught,  owing  to  their  inability  to  fiy,  do  not  die,  and  may  be  kept 
alive  for  years. 
9 


no  PHYSIOLOGY  OF   LODILY   EXERCISE. 

We  must  remark  that  not  every  animal  Which  dies 
from  fatigue  dies  of  breathlessness.  Hunted  animals 
usually  die  in  quite  another  manner,  which  we  shall 
study  under  the  name  of  overwork.  However,  in 
hunting  it  sometimes  happens  that  an  animal  is  forced 
to  run  without  stopping  until  it  dies.  This  is  the  case 
with  an  animal  which  breaks  cover,  and  trusts  to  ita 
speed  to  elude  the  hounds.  If  the  beast  is  too  young,  it 
may  be  taken  before  it  has  gained  the  wood  in  which  it 
hoped  to  find  new  shelter.  Then  it  is  breathlessness 
which  gives  it  up  to  the  hunter.  But  it  is  rare  for  this  to 
happen,  and  more  commonly  the  hunted  animal  stops 
from  time  to  time,  to  double  if  it  be  a  deer  or  a  hare,  or 
to  stand  at  bay  if  it  be  a  wild  boar. 

Even  these  very  short  rests  are  enough  for  the  animal 
to  render  its  respiration  regular,  and  to  eliminate  the 
excess  of  carbonic  acid  with  which  it  is  being  poisoned. 
After  a  minute  or  two  it  is  ready  to  start  afresh,  and  the 
chase  may  in  this  manner  hst  a  whole  day.  In  this  case, 
if  the  animal  is  in  the  end  hunted  to  death,  death  is  not 
due  simply  to  insufficiency  of  respiration  ;  it  results  from 
a  profound  decomposition  of  the  tissues,  which  we  shall 
study  in  the  chapter  on  Cz'cnvork 


CHAPTER  V. 

STIFFNESS. 

Return  to  the  Gymnasium  ;  A  Sleepless  Night — Febrile  Stiffness 
— Three  Degrees  of  Stiffness  of  Fatigue — Causes  of  Stiffness  ; 
Immunity  due  to  Habituation— Explanation  of  Symptoms  — 
Imperfection  of  Theories  —  Local  Symptoms  ;  They  are  due 
to  Trauma — General  Symptoms;  They  are  due  to  Auto- 
Intoxication —  Deposit  of  Urates  —  Influence  of  Muscular 
Exercise  on  their  Formation  ;  Diversity  of  opinion  of  Authors 
— Personal  Observations — Conditions  which  cause  Variations  in 
the  Formation  of  Deposits  after  Work — Slow  appearance  of  the 
Deposits  after  Exercise — Influence  of  the  Intensity  of  the  Work 
on  their  Formation — Hitherto  misunderstood  influence  of 
Training — Constant  Correlation  observed  between  the  Produc- 
tion of  Stiffness  and  the  Formation  of  Deposits — This  Correlation 
is  found  in  all  circumstances  which  render  the  Individual  more 
liable  to  Fatigue — Influence  of  Moral  Causes  on  Consecutive 
Fatigue  and  on  the  Deposits. 

If  a  person  has  for  some  months  taken  no  active  exer- 
cise, and  then  returns  to  the  gymnasium,  he  usually  finds 
at  the  outset  that  he  retains  all  his  old  vigour.  He  per- 
forms all  the  most  difficult  movements  with  as  much  ease 
as  when  they  were  assiduously  practised.  He  gives  him- 
self up  to  the  pleasure  of  long-discontinued  perform- 
ances, he  is  prodigal  with  the  work  of  his  muscles,  and 
finally,  after  a  long  practice,  he  goes  away  astonished  at 
feeling  no  fatigue  after  an  hour  so  well  spent 

In  the  evening,  however,  a  little  weariness  and  sleepi- 
ness make  him  think  that  the  violent  exercise  he  has 
taken  makes  him  need  more  sleep  than  usual,  and  he 
hastens  to  seek  in  sleep  the  reparation  of  the  force  he 
has  expended. 

But  sleep  does  not  come.     It  is  made  impossible  by 


112  THYSIOLOGY  OF   BODTLY   EXERCISE. 

excessive  agitation,  by  insupportable  heat  throug-hout  the 
body,  by  pains  in  the  head,  even  by  deHrium.  If  towards 
daybreak  he  goes  to  sleep  for  a  short  time,  he  awakes 
shaken,  bathed  in  sweat  ;  his  limbs  are  so  stiff  that  he 
cannot  move  them  ;  his  head  is  heavy,  his  tongue  coated, 
his  appetite  lost. 

During  the  day  the  fever  declines  ;  but  there  remains 
a  general  condition  of  discomfort,  of  inability  to  work,  a 
sensation  of  extreme  lassitude. 

Usually  after  twenty-four  hours  the  general  disturb- 
ances have  disappeared,  but  there  remain  local  sufferings, 
and  for  five  or  six  days  to  come  all  the  muscles  which 
have  taken  part  in  this  forced  exercise  remain  stiff*, 
painful  and  powerless. 

This  is  the  ordinary  picture  of  the  Stiffness  of 
fatigue. 

I. 

Stiffness  does  not  always  present  the  same  train  of 
symptoms,  for  there  are  several  degrees  of  it. 

If  the  exercise  we  have  not  practised  for  some  time 
be  executed  with  a  certain  moderation,  and  especially  if 
it  be  confined  to  localised  muscular  groups,  its  effect 
usually  remains  local,  and  is  limited  to  muscular  pains 
which  for  some  days  hinder  the  movement  of  the  limbs 
employed  in  the  exercise.  This  is  stiffness  of  the  first 
degree. 

If  the  muscular  efforts  have  been  intense  and  pro- 
longed, without  too  much  exceeding  the  power  of 
resistance  of  the  system,  general  disturbances  are  added 
to  the  local  pains,  and  produce  an  indefinable  sensation 
of  lassitude,  of  unfitness  for  work,  which  extends  even  to 
muscles  which  have  taken  no  part  in  the  exercise.  But 
the  pulse  remains  quiet,  nor  is  there  any  characteristic 
symptom  of  fever.  Slight  depression,  increased  sensi- 
bility to  cold,  are  the  only  witnesses  to  a  passing  dis- 
turbance of  health. — This  is  the  stiffness  of  the  second 
degree  ;  it  is  that  which  is  most  commonly  observed, 
and  that  which  we  shall  more  particularly  study. 

Finally,   when    the    exercise    has    been    excessively 


STIFFNESS.  113 

violent,  or  when  it  has  been  performed  by  one  whose 
system  possesses  little  power  of  resistance,  the  ensuing 
disturbance  takes  the  form  of  an  attack  of  fever.  This 
is  febrile  stiffness,  such  as  we  described  at  first. 

The  fever  of  stiffness,  a  typical  form  of  consecutive 
fatigue,  does  not  usually  begin  till  some  hours  after  the 
exercise  which  has  caused  it. 

It  may  be  ushered  in  by  a  rigor,  and  have  the  whole 
appearance  of  a  severe  febrile  affection.  The  severity 
of  the  symptoms  may  sometimes  lead  the  physician  to  a 
false  diagnosis,  and  make  him  suspect  the  onset  of  an 
eruptive  fever,  a  malarial  fever,  or  some  other  affection 
which  begins  with  severe  fever.  Moreover  in  some  cases  it 
may  last  longer  than  usual — for  three,  four,  or  more  days. 

The  intensity  of  the  stiffness  is  not  always  in  pro- 
portion to  the  hmuediate  fatigue,  to  that  which  is  felt 
during  the  exercise,  and  which  forces  the  muscles  to 
rest.  Exercise  is  sometimes  followed  by  stiffness  without 
having  been  accompanied  by  any  muscular  fatigue 
during  its  performance.  Sometimes,  on  the  other  hand, 
an  exercise  is  pushed  to  the  utmost  limits  of  a  man's 
powers,  without  the  slightest  disturbance  following. 

This  is  because  stiffness  depends  rather  upon  the 
conditions  of  the  worker,  than  on  those  in  which  he 
performs  the  work.  A  moderate  exercise,  such  as 
walking,  may  result  in  febrile  stiffness  in  a  man  accus- 
tomed to  complete  inactivity,  while  running  or  fencing 
will  produce  in  a  well-trained  man  not  even  a  local 
consecutive  disturbance. 

Before  examining  the  reasons  for  this  immunity  pro- 
duced by  habit,  it  is  necessary  to  establish  the  cause  and 
the  mechanism  of  stiffness. 

And  first  we  must  divide  in  two  classes  the  phenomena 
observed  in  persons  suffering  from  stiffness.  We  must 
study  separately  the  local  symptoms  and  the  general 
symptoms  of  this  form  of  fatigue. 

The  local  symptoms  have  been  more  studied  than  the 
others,  but,  according  to  Richet,*  they  have  not  yet  been 

•  Richet.     Les  Muscles  et  les  Nerfs. 


114  PHYSIOLOGY  OF   BODILY  EXERCISE. 

satisfactorily  explained.  Under  the  influence  of  the 
organic  combustions  which  accompany  muscular  work, 
an  excess  of  lactic  acid  is  produced  in  muscle.  Accord" 
ing  to  the  recognised  theory,  this  substance,  impregnating 
and  saturating  the  muscular  fibre,  caus'^s  it  for  the  time 
tc  lose  its  contractile  power. 

"  But  firstly,"  says  Richet,  "  recent  experiments  have 
shown  that  little  lactic  acid  is  produced  during  contrac- 
tion. Secondly,  the  alkaline  blood  passing  constantly 
through  the  muscle  would  instantaneously  neutralise 
the  lactic  acid  formed.  Finally,  how  do  you  explain 
that  several  days  after  the  fatigue,  this  or  that  muscle 
remains  painful?  Assuredly  there  no  longer  remains  a 
trace  of  the  lactic  acid  produced  by  the  contractions  of 
seventy-six  hours  before."  * 

We  believe  that  the  persistent  local  pains  of  stiffness 
are  to  be  explained  by  a  series  of  small  material 
lesions. 

If  we  submit  any  region  of  the  body  to  violent 
compressions,  to  prolonged  manipulations  like  those 
which  would  result  from  an  excessively  violent  message, 
we  produce  in  the  muscular  masses  thus  treated,  per- 
sistent painful  phenomena,  perfectly  analogous  to  the 
muscular  pains  of  stiffness. 

On  the  other  hand  we  often  see  excessive  work  produce 
in  muscles,  tendons,  and  synovial  membranes,  a  series  of 
lesions  exactly  similar  to  those  which  would  be  produced 
by  external  violence.     Inflammation  of  muscles  running 

"*'  Lactic  acid,  however,  plays  an  important  part  in  the  local 
phenomena  of  stiffness.  But  its  action  is  transient.  To  the 
presence  of  lactic  acid  we  must  attribute  the  stiffness  which  is 
almost  instantaneously  produced  in  an  overworked  limb  when  the 
circulation  in  it  begins  to  slacken  during  repose.  This  stiffness, 
which  makes  it  so  painful  to  resume  work,  is  dissipated  by  a  few 
energetic  efforts,  which  re-establish  the  circulation  in  the  muscles. 
The  stiffness  which  comes  on  with  repose  is  not  so  much  due  to 
the  cooling  of  the  muscle  as  to  the  slowing  of  the  circulation.  When 
the  muscle  ceases  to  contract,  the  blood  does  not  so  freely  bathe 
the  muscle  fibre.  "When  work  is  resumed,  the  blood-current,  more 
active  again,  carries  away  the  lactic  acid  with  which  the  fibre  is 
impregnated,  and  further,  thanks  to  its  alkalinity,  it  neutralises 
this  acid. 


STIFFNESS.  115 

on  to  suppuration,  inflammation  of  synovial  sheaths  with 
painful  crepitation  of  tendons,  may  result  from  overwork 
of  motor  organs,  just  as  from  external  violence.  This  is 
because  the  mechanism  of  the  accidents  is  in  both  cases 
the  same. 

The  muscular  pain  felt  in  a  muscle  which  has  done 
too  much  work  is  only  the  first  degree  of  a  series  of 
small  lesions  similar  to  those  which  are  observed  after 
any  injury.  We  need  be  no  more  astonished  at  the 
prolonged  painfulness  of  the  muscular  fibre  bruised  by 
unusual  work,  than  by  the  persistence  of  blisters  on  the 
skin  irritated  by  a  body  which  the  hand  is  not  used  to 
hold.  A  series  of  small  lesions  of  the  motor  organs 
may  result  from  violent  exercise.  We  can  make  no 
better  comparison  than  to  the  different  injuries  which 
may  be  produced  in  a  machine  by  excessive  work.  Just 
as  in  the  machine,  the  bands  may  become  loose,  the 
bearings  roughened  and  the  oil  dried  up. 

But  the  general  phenomena  of  consecutive  fatigue 
cannot  be  explained  mechanically.  They  are  of  an 
essentially  vital  order,  and  have  no  analogies  in  any 
machine  constructed  by  the  hand  of  man. 

Febrile  stifi'ness  has  the  general  appearance  of  a  mild 
infectious  disease.  It  resembles  most  nearly  intermittent 
fever,  if  we  suppose  the  latter  to  be  limited  to  one  attack. 
Mild  septic  intoxications  have  also  a  very  marked  resem- 
blance to  the  fever  of  fatigue.  It  is  the  same  with  the 
onset  of  the  eruptive  fevers,  and  with  all  febrile  states 
characterised  by  the  presence  within  the  economy  ot 
an  injurious  substance,  against  which  the  vital  organs 
re-act. 

Does  not  the  resemblance  of  the  symptoms  point  to 
a  similar  cause,  and  can  we  not  refer  stiffness  to  an 
infectious  process  or  a  poisonous  material  ?  We  know 
that  the  combustions  of  muscular  work  produce  changes 
in  the  living  tissues  which  profoundly  alter  their  struc^ 
ture,  and  we  know  further  that  the  products  resulting 
from  these  phenomena  of  combustion,  or  dissiniilation 
are  dangerous  to  life,  and   must  be  speedily  eliminated 


Il6  PHYSIOLOGY  OF   BODILY   EXERCISE. 

from  the  system,  under  pain  of  severe  disorders,  and 
symptoms  of  poisoning.  The  study  of  breatJilessness 
has  shown  us  that  this  form  of  fatigue  is  an  auto- 
intoxication by  carbonic  acid,  a  product  of  dissimilation. 
Might  not  the  consecutive  fatigue  called  stiffness  be 
caused  by  a  transient  intoxication  of  the  system  by  the 
products  of  its  own  activity  ?    . 

Let  us  examine  how  far  the  physiology  of  muscular 
work  can  help  us  to  solve  this  question. 

We  know  that  local  muscular  fatigue,  and  the  loss  of 
irritability  resulting  from  excessive  work,  are  due  to  a 
chemical  change  in  the  structure  of  the  organ,  and  to 
the  formation  of  certain  new  organic  products.  The 
composition  and  exact  nature  of  these  substances, 
resulting  from  the  dissimilation  of  the  anatomical 
elements  are  still  in  dispute,  but  their  physiological 
effects  are  known.  We  know  that  these  waste  products 
are  the  cause  of  the  loss  of  irritability  of  the  fatigued 
muscle,  and  that  their  contact  with  the  motor  fibres 
prevents  the  latter  from  responding  to  electrical  stimuli, 
or  to  the  will. 

We  know  further  that  these  substances,  with  which 
the  fatigued  muscle  is  impregnated,  have  the  curious 
property  of  making  their  fatiguing  power  felt  by  the 
muscular  elements  of  another  organism.  In  fact,  by 
injecting  into  the  muscles  of  a  healthy  frog  a  soup  made 
from  a  finely-powdered  fatigued  muscle,  the  muscles  of 
the  frog  lose  their  irritability  and  become  unable  to 
contract. 

Among  the  products  of  dissimilation  of  muscle  are 
there  not  some  substances  which  have  a  poisonous 
action  on  the  whole  organism,  and  produce  the  general 
discomforts  and  febrile  disturbances  of  stiffness? 

But  stiffness  only  occurs  after  exercise  in  certain 
special  circumstances  :  in  case  the  person  is  out  cf 
practice  in  the  exercise  he  is  performing.  We  must  find 
then  products  of  dissimilation  which  are  not  constantly 
formed  during  work,  but  the  appearance  of  which 
depends  on  the  want  of  practice  in  the  work,  or  the 
want  of  training. 


STIFFNESS.  117 

Now  we  have  been  able  to  make  a  series  of  observa- 
tions proving  that  certain  organic  waste-products  are 
invariably  formed  after  an  exercise  when  the  person 
performing  it  is^not  in  training,  and  that  these  waste- 
products  are  not  found  when  the  person  habitually 
practises  this  exercise.  We  have  many  times  been  able 
to  assure  ourselves  that  there  is  a  constant  coincidence 
between  the  formation  of  these  waste-products  and  the 
production  of  stiffness,  and  we  have  ventured  to  estab- 
lish between  these  two  phenomena  a  relation  of  cause 
and  effect. 

II. 

It  is  among  the  waste-products  eliminated  in  the 
urine  after  muscular  work,  that  it  is  necessary,  in  our 
opinion,  to  seek  the  substances  capable  of  causing  the 
general  disturbances  of  stiffness. 

Which  is  the  exact  substance,  among  those  which  we 
find  in  the  urine,  which  has  the  property  of  producing 
these  disturbances  ?  We  do  not  know  the  exact  sub- 
stance, but  we  can  affirm  that  it  is  contained  in  the 
deposits  of  urates. 

These  deposits  are  known  to  all  observers  as  being 
formed  in  the  urine  after  violent  exercise.  Everyone 
will  have  observed  the  turbid  appearance  presented  by 
his  urine  Vv^hen  it  has  stood  some  hours  after  a  very  long 
walk,  or  a  first  day's  hunting,  when  he  is  not  yet  accus- 
tomed to  fatigue.  These  deposits,  which  indicate  the 
saturation  of  the  urine  by  sparingly  soluble  substances, 
are  only  formed  after  some  hours,  when  the  liquid  has 
become  cold.  The  urine  has  then  usually  a  whitish 
yellow  colour  which  makes  it  resemble  pus  ;  sometimes 
the  tint  is  reddish,  recalling  the  colour  of  brick-dust. 
But  if  we  warm  in  a  test  tube  a  small  quantity  of  this 
turbid  urine,  it  at  once  becomes  clear,  owing  to  solution 
of  the  precipitate,  which  is  more  soluble  in  hot  than  in 
cold  water.     On  cooling,  the  turbidity  reappears. 

This  simple  test  is  sufficient  to  prove  that  the  deposits 
in  the  urine  after  muscular  work  consist  for  the  most 
part    of   urates.      We    shall    see,    after    a    methodical 


Il8  PHYSIOLOGY  OF   BODILY  EXERCISE. 

analysis,  that  they  consist  of  alkah'ne  and  ammoniacal 
urates.  For  this  reason  we  give  them  with  Neubauer* 
the  name  of  deposits  of  urates. 

All  authors  agree  in  recognizing  that  the  appearance 
of  the  urine  can  be  modified  by  muscular  work,  but 
they  are  far  from  agreeing  about  the  conditions  under 
which  this  modification  is  produced. 

According  to  Béclard,t  muscular  exercise  dimiîiishes 
the  amount  of  uric  acid  and  urates  in  the  urine. 

According  to  Lécorché,|  exercise  increases  the  amount 
of  uric  acid  and  urates  in  the  urine. 

After  these  two  absolutely  contradictory  statements 
we  will  quote  two  others  which  seem  contradictory. 

Bouchard  §  declares  that  moderate  ex<ircise  causes 
the  disappearance  from  the  urine  of  deposits  which  it 
ordinarily  contains,  and  violent  exercise  causes  the 
appearance  of  some  not  ordinarily  formed. 

Guyon  i|  says  that  slight  exercise  increases  the  amount 
of  uric  acid  and  urates,  and  an  active  life  causes  their 
diminution. 

If  the  authors  we  have  quoted  have  the  same  opinion 
on  this  question,  we  must  agree  that  they  express  it  in 
very  different  fashions,  and  that  it  is  difficult,  after 
reviewing  their  conclusions,  to  get  any  clear  idea  of  the 
effect  of  work  on  the  formation  of  deposits  of  urates. 

If  we  endeavour  to  form  a  personal  opinion  on  this 
question,  with  the  help  of  careful  observation,  we  see 
that  there  are  many  causes  of  error  which  can  render 
the  observations  incorrect,  for  many  circumstances 
besides  exercise  cause  the  appearance  of  deposits  in  the 
urine.  We  must  first  ascertain  that  the  person  on  whom 
we  experiment  has  not  ordinarily  deposits  in  his  urine, 
such  as  occur  in  most  men  who  lead  a  very  sedentary 
life.  Next  we  must  be  sure  that  he  is  exposed  to  none 
of  the  numerous  causes  which  can  accidentally  provoke 

*  Neubauer.     l'Urine. 

+  Béclard.     Physiologic. 

X  Lécorché.     La  Goutte. 

§   Bouchard.     Le  Ralentissement  de  la  Nutrition. 

Il  Guyon.     Maladies  des  voies  urinaires. 


STIFFNESS.  ïig 

the  appearance  of  these  deposits.  Wc  know  that  pro- 
longed vii^ils,  severe  mental  work,  excesses  in  eating, 
often  produce  this  phenomenon.  Finally  we  must  know 
that  he  suffers  from  no  constitutional  or  transitory- 
pathological  condition  capable  of  producing  turbidity  in 
the  urine  ;  gout  and  fever,  for  example.  In  short  we 
must  know  well  his  habits,  his  antecedents,  his  actual 
condition  of  health,  and  his  mode  of  life. 

Under  these  circumstances,  the  best  person  the  ob- 
server can  choose  for  his  studies,  is  himself  when  in  a 
condition  of  perfect  health.  It  is  then  on  ourselves  that 
we  have  made  the  observations  we  are  about  to  describe. 
But  we  have  carefully  repeated  them,  as  a  check,  on 
several  persons  with  whose  constitutions  and  mode  of 
life  we  were  thoroughly  familiar,  and  who,  for  the  most 
part,  performed  in  our  company  various  bodily  exercises. 

The  results  of  our  observations  may  be  summed  up  as 
follows  : — 

When  a  healthy  man  of  a  temperate  habit,  active 
and  regular,  performs  a  bodily  exercise,  the  appearance 
of  his  urine  varies  much  according  to  three  different  cir- 
cumstances :  (i)  the  time  when  it  is  examined,  (2)  the 
greater  or  less  violence  of  the  exercise,  (3)  the  greater 
or  less  "  habituation  "  to  the  exercise. 

With  regard  to  the  time  when  the  li'^uid  is  examined, 
it  is  hardly  necessary  to  mention  a  circumstance  which  is 
as  important  as  it  is  well  known  :  the  urines  which  will 
deposit  urates  become  turbid  only  when  they  have  cooled, 
and  are  always  clear  at  the  time  they  are  passed.  By 
the  side  of  this  well  known  fact  there  is  another  which 
we  believe  we  are  the  first  to  point  out  :  namely  that 
muscular  exercise  does  not  make  its  influence  on  the 
urine  apparent  ////  tJie  end  of  a  certain  number  of  hoiirs. 

It  is  important  to  be  well  aware  of  this.  Supposing 
we  perform  a  muscular  exercise  in  the  conditions  which 
are  necessary  to  produce  in  the  urine  the  subsequent 
changes  of  which  we  have  spoken.  Suppose  too  that 
we  have  been  careful  to  empty  the  bladder  immediately 
before  the  exercise,  so  that  no  liquid  formed  before  the 
work,  is  left.      If  we  then  begin  fencing  or  rowing,  the 


120  PHYSIOLOGY  OF   BODILY  EXERCISE. 

bladder  gradually  fills  with  urine  secreted  during  and 
after  the  exercise.  If  we  then  collect  in  different  vessels 
the  urine  passed  at  different  intervals,  every  hour  for 
instance,  we  shall  have  a  series  of  samples  of  urine 
secreted  since  the  exercise  began,  some  during  it,  and 
some  after  it. 

If  we  then  place  these  different  samples  in  their  chro- 
nological order  and  keep  them  till  the  next  day,  this  is 
what  we  notice  : 

The  urine  passed  immediately  after  the  exercise  is 
perfectly  clear,  and  so  is  that  passed  one,  or  two  hours 
afterwards.  It  is  only  in  the  vessel  containing  the  urine 
secreted  during  the  third  hour  after  the  cessation  of  the 
work,  that  the  first  cloudiness,  due  to  deposit  of  urates, 
is  usually  manifested.  This  phenomenon  has  never 
varied  in  experiments  made  on  six  or  seven  persons  of 
different  ages  or  temperaments,  but  all  in  good  health  and 
under  normal  circumstances  having  clear  urine  :  and 
the  deposits  due  to  muscular  work  have  not  appeared  in 
the  urine  till  three  hours  after  the  cessation  of  the  exer- 
cise. On  the  other  hand,  in  some  persons,  the  urine  has 
been  clear  for  a  longer  period  ;  we  have  seen  cases  in 
which  no  deposit  occurred  in  the  urine  for  six  or  seven 
hours  after  the  exercise. 

At  the  risk  of  repeating  ourselves  we  wish  to  make  it 
clearly  understood  that  this  delay,  averaging  three  or 
four  hours,  does  not  apply  to  the  time  elapsing  between 
the  passing  of  the  urine  and  the  formation  of  the  preci- 
pitate, but  to  the  time  which  separates  the  end  of  the 
exercise  from  the  time  when  the  urine  is  secreted.  More- 
over, the  urine  which  will  form  deposits  is  passed,  as 
usual,  quite  clear,  and  becomes  turbid  more  or  less 
quickly  according  to  the  rapidity  with  v/hich  it  cools. 

Here  then  we  have  a  first  fact  :  t/ie  iirinai'y  deposits 
which  a7e  observed  in  man  after  zvork  nnist  only  be 
looked  for  in  urine  passed  at  least  tJiree  hours  after  exer- 
cise. 

This  may  be  one  cause  of  errors  of  observations.  Tf 
we  examine  only  the  urine  passed  an  hour  after  work, 


STIFFNESS.  121 

we  shall  never  find  deposits  of  urates,  and  we  mii^^ht 
conclude  that  exercise  never  caused  their  production, 
though  they  would  show  themselves  very  abundantly  in 
the  urine  of  the  third  or  fourth  hour,  which  we  have  not 
examined. 

But  we  can  draw  another  conclusion  from  our  observa- 
tions :  namely  that  the  organic  substances  forming  these 
precipitates  are  slowly  eliminated,  and  stay  long  in  the 
economy  before  passing  through  the  renal  filter.  Now 
we  know  that  the  kidney  does  not  elaborate  the  sub- 
stances which  are  found  in  the  urine,  but  that  it  elimi- 
nates them  as  they  are  brought  to  it  by  the  blood.  The 
excrementitious  materials,  which  are  the  waste  products 
of  muscular  work,  are  then  ready  formed  in  the  system 
before  passing  through  the  excretory  organ.  They  can 
make  their  injurious  influence  felt  for  a  long  time,  for 
they  stay  several  hours  in  the  economy. 

We  m.ust  add  that  this  production  of  deposits  of 
urates  which  begins  three  hours  after  the  work,  continues 
sometimes  for  twenty-four  hours,  that  is  as  long  as  the 
general  disorders  of  fatigue. 

The  time  when  the  precipitate  is  observed  being  thus 
established,  it  is  easy  to  study  the  influences  on  its  pro- 
duction, firstly  of  the  conditions  under  which  the  work  is 
done,  and  secondly  of  the  physiological  condition  of  the 
worker. 

If  the  work  is  not  very  severe  and  of  short  duration 
there  will  be  no  precipitate.  The  precipitate  is  very 
abundant  on  the  other  hand  when  the  exercise  is  very 
violent  and  very  prolonged.  In  the  same  individual  the 
urinary  deposits  are  more  abundant,  and  appear  during 
a  longer  period,  the  more  intense  and  more  sustained  the 
muscular  work  necessitated  by  the  exercise.  According 
to  the  greater  or  less  violence  of  the  exercise,  the  preci- 
pitate will  vary  from  a  faint  cloud  in  only  one  of  the 
specimens,  to  the  thickest  deposits  rendering  turbid  and 
muddy  all  the  urine  passed  during  twenty-four  hours. 

But  the  condition  of  the  individual  has  much  more 
influence  than  the  severity  of  the  exercise  in   increasing 


122  PHYSIOLOGY  OF   BODILY  EXERCISE. 

or  diminishing  the  quantity  of  deposit  formed  after 
the  work.  The  nearer  he  approaches  to  the  condition  of 
training,  the  less  abundant  the  deposits  in  the  urine,  the 
amount  of  work  remaining  the  same.  In  proportion  as 
from  practice  he  acquires  more  power  of  resisting  fatigue, 
his  urine  loses  the  tendency  to  deposit  urates. 

There  is  nothing  more  interesting  than  to  follow  the 
inverse  progression  of  these  two  phenomena  :  power  of 
resisting  fatigue,  and  the  formation  of  urinary  deposits. 
If  the  same  individual  does  every  day  the  same  exercise, 
demanding  the  same  expenditure  of  force;  if  he  undertakes 
for  instance,  to  row  a  certain  distance  in  an  hour  every 
day,  his  exercise,  which  causes  great  stiffness  during  the 
first  few  days,  hardly  produces  any  disturbance  after  a 
week's  practice.  His  urine  which  at  first  gave  abundant 
deposits,  shows  later  only  a  faint  cloud. 

As  the  deposit  becomes  smaller,  the  sensation  of 
consecutive  fatigue  tends  to  diminish,  and  when  the 
urine  keeps  perfectly  clear  after  the  exercise,  he  will 
suffer  from  no  kind  of  discomfort  :  there  will  be  no  stiff- 
ness. There  is  then  a  close  relation,  an  invariable  coin- 
cidence between  the  formation  of  deposits  of  urates  and 
the  production  of  stiffness. 

This  remarkable  correlation  is  found  in  all  circum- 
stances which  can  alter  the  effects,  of  work.  If  we  pass 
from  an  exercise  with  which  we  are  familiar,  to  another 
exercise  calling  into  action  a  different  muscular  group, 
we  experience  afresh  the  discomfort  of  stiffness,  and  our 
urine  again  shows  a  deposit.  Thus,  a  man  used  to 
forced  marches,  experiences  no  consecutive  fatigue  on 
the  day  following  a  long  journey  made  on  foot.  He 
will,  however,  suffer  from  stiffness,  if,  without  being  used 
to  it,  he  spends  a  short  time  hi  fencing.  If  we  examine 
his  urine,  we  shall  discover  that  though  it  remained  per- 
fectly clear  after  twelve  hours'  walking,  it  is  very  turbid 
after  twenty  minutes'  fencing.  This  will  always  be  the 
result  when  we  undertake  a  new  kind  of  work,  which 
brings  into  play  muscles  not  hitherto  exercised. 

The  close  correlation  between  stiffness  of  fatigue  and 


STIFFNESS.  123 

the  formation  of  excrcmcntitious  products  which  make 
the  urine  turbid,  may  be  ascertained  even  in  accidental 
circumstances  which  make  the  resistance  of  the  indivi- 
dual variable,  and  render  him  for  a  time  more  vulnerable 
to  fatigue.  Under  the  influence  of  slight  indisposition, 
of  an  insignificant  disturbance  of  health,  it  often  hap- 
pens, as  all  amateurs  of  sport  know,  that  the  aptitude 
for  work  is  for  the  time  diminished.  On  these  days  the 
gymnast  has  not  his  accustomed  vigour,  and  the  exercise 
is  followed  by  a  long-forgotten  sensation  of  discomfort. 
A  man  well  broken  in  to  his  work  shows,  under  these 
circumstances,  the  same  phenomena  of  fatigue  as  a 
novice,  and  his  urine,  which  for  a  long  time  has  always 
remained  clear  after  exercise,  begins  again  to  deposit 
urates. 

We  have  many  times  observed  these  facts  on  ourselves, 
and  have  been  able  also  to  record  them  on  other  persons, 
as  the  following  observation  shows. 

A  friend  of  ours,  a  good  oarsman,  in  perfect  training, 
offered  himself  for  our  studies  on  the  changes  in  the 
urine  produced  by  w^ork  ;  but  he  was  so  inured  to  mus- 
cular exercise  that  we  could  never  find  the  slightest 
deposit  in  his  urine.  One  morning  we  were  rowing  with 
him  in  the  same  boat,  and  we  were  surprised  to  see  that 
he  was  wanting  in  his  accustomed  vigour  ;  he  needed  all 
his  force  of  will  to  go  on  rowing  to  the  end  of  his  ordinary 
course.  Two  nights  without  sleep  had  brought  about 
this  temporary  enfeeblement.  On  this  occasion  the 
exercise  left  him  throughout  the  entire  day  with  a  sen- 
sation of  discomfort  and  stiffness,  such  as  he  had  never 
experienced,  and  his  urine,  which  for  a  long  time  had 
been  very  clear  after  work,  showed  very  abundant  de- 
posits of  urates. 

Whenever  the  organism  is  in  a  condition  of  "  dimi- 
nished resistance,"  there  is  a  tendency  to  the  formation  of 
deposits  of  urates,  and  a  tendency  also  to  a  manifestation 
of  the  symptoms  of  stiffness. 

It  may  happen  that  the  deficient  resistance  of  the 
organism  is  produced  by  a  cause  of  the  moral  order,  by 


124  PHYSIOLOGY  OF  BODILY   EXERCISE. 

mental  abstraction,  by  depressing  emotion.  We  have 
been  able  to  ascertain  that,  in  this  condition  of  physical 
and  moral  depression,  a  well-trained  man  loses  for  a 
time  his  immunity  from  fatigue,  and  shows,  after  mus- 
cular exercise,  all  the  symptoms  of  stiffness  ;  but,  at  the 
same  time,  his  urine  is  not  clear  as  usual  after  work,  but 
deposits  urates.  We  have  observed  this  phenomenon  in 
a  man  who  was  a  great  fencer,  inured  to  all  forms  of 
exercise.  He  fenced  every  day,  witn  no  symptoms  of 
stiffness,  and  no  deposit  in  his  urine.  One  day,  after  a 
short  fencing  bout,  when  his  mind  was  preoccupied  with 
thoughts  of  a  serious  duel  he  had  to  fight  on  the  fol- 
lowing day,  he  suffered  from  a  very  severe  attack  of 
stiffness,  and  we  found  an  abundant  precipitate  in  his 
urine. 

Such  are  the  facts  of  experiment  and  observation 
showing  the  constant  correlation  between  the  formation 
of  deposits  of  urates  and  the  production  of  the  stiffness  of 
fatigue.  Every  circumstance  which  makes  a  man  more 
vulnerable  to  fatigue,  causes  at  the  same  time  a  tendency 
to  the  formation  of  deposits  in  his  urine. 

Between  these  two  phenomena,  excretion  of  turbid 
urine,  and  discomfort  following  exercise,  there  is  so  con- 
stant a  correlation,  that  it  is  impossible  not  to  see  in 
them  a  relation  of  cause  and  effect. 


CHAPTER  VI. 
STIFFNESS  {continued). 

Objection  to  Our  Theory— Are  Urinary  Deposits  due  to  the 
Perspiration  produced  by  Exercise  ?^Observations  opposed  to 
the  opinion  of  Authors  on  this  Subject — An  Experiment  in 
Fatigue: — Rowing:  from  Limoges  to  Paimbœuf — Agreement  of 
Observations  with  Chemical  Analysis —Exercise  produces  a 
Uricaemic  condition— Analogy  of  Stiffness  of  Fatigue  with 
certain  Febrile  conditions — i)tirfhess  of  Fatigue  and  an  Attack 
of  Gout — Cause  of  Immunity  from  Stiffness  when  in  Training — 
Function  of  Reserve  Materials  — Products  of  Dissimilation — Part 
played  by  Uric  Acid  in  Stiffness — Stiffness  is  an  Auto- 
Intoxication.  ; 

Î. 

An  objection  first  presents  itself  against  the  conclusion 
we  have  just  formulated. 

Some  authors  consider  urine  which  forms  deposits  after 
muscular  exercise  not  as  a  liquid  containing  more  excre- 
mentitious  materials  than  in  the  ordinary  condition,  but 
as  a  more  concentrated  liquid,  that  is  to  say,  one  con- 
taining less  water  for  the  same  quantity  of  solids  in 
solution.  Urinary  deposits  are  not  more  abundant  in 
urine  after  exercise,  but  the  water  which  holds  them  in 
solution  is  less.  Hence  more  saturation  of  the  liquid 
and  tendency  to  precipitation.*  If  the  theory  of  these 
authors  were  true,  these  urinary  deposits  would  not 
indicate  any  change  in  the  chemical  composition  of  the 
liquid  ;  they  would  merely  mean  that  a  part  of  the  water 
ordinarily  eliminated  by  the  kidney  has  been  discharged 
by  other  channels,  and  notably  by  the  skin.     Excessive 

*  Dictionnaire   de   medicine    et   de    chirurgie    pratique.      Art. 

"  Urine." 

10 


126  PHYSIOLOGY  OF  BODILY  EXERCISE. 

perspiration  would  then  be  the  true  cause  of  the  forma- 
tion of  the  deposits. 

Two  strong  arguments  can  be  opposed  to  this  theory. 

In  the  first  place  the  urine  is  often  just  as  abundant 
on  the  days  when  there  are  deposits,  as  on  the  days 
when  there  are  none.  We  have  established  this  by  fifty 
observations  on  different  persons.  It  often  happened 
during  these  observations  that,  perspiration  having  been 
but  slight,  and  urine  more  abundant  than  usual,  the 
deposits  were  none  the  less  formed,  in  a  person  unac- 
customed to  work.  On  the  other  hand,  we  have  been 
able  to  ascertain  that,  in  perfectly  trained  men,  profuse 
sweats  often  occur  during  exercise  without  any  subse- 
quent turbidity  of  the  urine. 

A  long  observation  of  fatigue,  made  on  a  friend  and 
on  ourselves,  has  enabled  us  to  confirm  through  nine 
successive  days  the  result  of  the  studies  we  had  already 
made,  and  certainly  to  give  them  more  weight. 

In  the  beginning  of  August  1886,  we  set  out  in  a  boat 
intending  to  row  in  as  short  a  time  as  possible  from 
Limoges  to  Paimbœuf.  In  nine  days  we  covered  the 
distance  of  341  miles  with  double  sculls,  having  further 
an  excessive  supplementary  work  in  dragging  our  boat 
up  the  high  and  nearly  dry  weirs,  which  to  the  number 
of  83  interrupt  the  course  of  the  Vienne. 

This  great  expenditure  of  muscular  force  never  made 
us  stiff,  for  we  had  both  been  hardened  by  two  months' 
training.  After  working  twelve  or  fourteen  hours  in  the 
sun  on  the  hottest  days  of  the  year,  we  suffered  in  many 
ways,  but  never  from  stiffness  ;  we  never  found  ourselves 
on  rising  in  the  morning  less  disposed  for  work  than  the 
night  before,  although,  while  working,  fatigue  was  carried 
to  its  utmost  limits,  and  when  we  left  the  oars  our 
strength  was  exhausted.  The  exercise  had  been  pushed 
to  the  degree  of  overwork,  for,  in  spite  of  a  very 
substantial  diet  washed  down  with  some  wine  and  a 
great  deal  of  coffee,  we  each  of  us  lost  ten  pounds  in 
weight  in  the  nine  days.  But  we  were  never  attacked 
by  stiffness,  and  our  urines,  examined  day  by  day,  neve? 
presented  the  least  deposit  of  urates. 


STIFFNESS.  127 

If  however  these  deposits  were  the  result  of  excessive 
perspiration,  no  opportunity  could  have  been  more 
favourable  to  their  formation  than  the  second  day 
of  our  voyage,  of  which  I  will  give  you  an  exact 
account. 

On  the  loth  of  August,  after  rowing  31  miles  under 
a  burning  sun,  which  had  covered  our  necks,  faces,  and 
hands  with  blisters,  having  saturated  our  thick  sweaters 
with  perspiration,  we  put  up  for  the  night  in  the  little 
town  of  Availles,  of  which  the  innkeeper  was  at  the 
same  time  the  baker.  We  had  to  sleep  in  enormous 
feather-beds  in  which  we  sank  up  to  the  chin,  in  a  night 
following  one  of  the  dog-days.  Finally  our  host,  as  if 
wishing  to  give  us  all  the  elements  necessary  for  a 
phvsiological  experiment,  had  given  us  a  room  directly 
over  the  chimney  of  his  fire  which  burned  throughout 
the  night. 

It  is  impossible  to  imagine  a  more  complete  collection 
of  conditions  calculated  to  provoke  sweating  ,  forced 
work  for  ten  hours  under  an  August  sun  ;  a  night 
spent  in  a  feather  bed  in  a  room  heated  like  an  oven. 
The  following  day,  an  injury  to  the  boat,  which  had  to  be 
repaired,  compelled  us  to  stay  half  a  day  in  the  village, 
and  we  had  ample  leisure  to  examine  the  urine  we 
passed  during  several  hours.  But  in  spite  of  the  profuse 
sweats  which  had  saturated  our  clothing  by  day,_and 
inundated  our  beds  by  night,  there  was  no  deposit  in 
either  of  our  urines. 

Thus  it  is  not  enough  to  sweat  much  during  and  after 
work  in  order  to  form  deposits  in  the  urine.  Excessive 
perspiration  will  produce  in  persons  in  training,  as  in 
anyone  else,  a  diminution  in  the  quantity  of  urine  passed, 
but  does  not  necessarily  determine  the  appearance  of 
deposits  of  urates. 

A  last  proof,  which  is  of  course  the  most  convincing, 
establishes  the  real  increase  in  the  uric  acid  and  urates 
in  nrine  presenting  a  deposit  of  urates  after  exercise  ; 
tliis  is  chemical  analysis. 

Here  is  the  result  of  the  examination  of  a  sample  of 
urine  passed  after  a  long  fencing  bout  by  a  person   not 


128  PHYSIOLOGY  OF  BODILY  EXERCISE. 

in  training,  who  had  abstained  from  all  active  muscular 
exercise  for  two  months.* 

In  a  litre  of  urine  the  quantity  of  uric  acid  eliminated 
was  r43  grammes. 

"  In  the  same  person  who  had  performed  the  same 
work  after  a  course  of  training,  in  whose  urine  there  was 
no  deposit,  a  litre  of  this  liquid  contained  0'6  gramme,  a 
quantity  which  does  not  exceed  the  normal. 

We  see  then  that  after  the  performance  of  the  same 
muscular  work,  the  untrained  man  eliminates  rather 
more  than  double  the  quantity  of  uric  acid,  while  in  the 
trained  man  there  is  no  increase  in  this  product. 

The  facts  which  we  bring  to  the  study  of  the  changes 
produced  in  urine  by  muscular  work  are  evidently  very 
incomplete,  for  they  point  out  one  fact  only  ;  the 
formation  of  a  deposit  of  urates  ;  but  this  fact  alone  is 
interesting  to  determine,  and  the  more  so  because 
hitherto  no  one  had  pointed  out  its  close  correlation 
with  the  general  disturbance  of  stiffness. 

We  are  able,  after  the  preceding  study,  to  establish 
one  fact  ;  that  the  proportion  of  uric  acid  eliminated  is 
much  increased  when  the  urine  becomes  cloudy  after 
exercise.  Now  the  urine  merely  serves  for  the  discharge 
from  the  system  of  products  already  existing  in  the 
blood.  The  excess  of  uric  acid  which  we  have  found  in 
the  urine  after  muscular  exercise,  must  then  have  existed 
in  the  blood  before  it  passed  into  the  urine.  We  know 
further  that  the  elimination  of  urates  does  not  begin  till 
three  hours  after  exercise  and  continues  for  some  time, 
for  twenty-four,  or  even  thirty-six  hours.  Throughout 
this  period  the  system  has  been  exposed  to  the  influence 
of  an  excess  of  uric  acid. 

Violent  exercise  then  leaves,  in  persons  who  are  not 
trained,  an  excess  of  uric  acid  in  the  blood,  a  true 
tiric<'3emic  condition,  similar  to  that  which  is,  for  instance, 
observed  in  gouty  subjects  just  before  an  attack  of  gout. 

*  This  analysis  was  made  by  M.  Papon,  experimental  chemist, 
whom  we  wish  here  to  thank  for  the  assistance  he  has  so  willingly 
given  us. 


STIFFNESS.  129 


II. 


Is  it  to  this  excess  of  uric  acid  that  we  must  attribute 
the  disorders  felt  after  violent  exercise  ?  ,  •      , 

Evidently  among  the  waste  products  elimmated  m  the 
urinary  deposits  there  must  be  many  other  substances 
which  could  make  their  influence  on  the  system  felt 
durino-  their  prolonged  stay  in  the  blood  before  bemg 
eliminated.  It  is  certain  that  the  extractives  such  as 
kreatinin,  xanthin,  and  other  products  of  mcomplete 
combustion,  have  an  important  part  in  the  production  of 
the  febrile  disturbances  of  consecutive  fatigue.  But  the 
physiological  relations  of  these  substances  are  as  yet  so 
little  known,  that  it  is  advisable  to  speak  of  their 
probable  influence  with  the  greatest  possible  reserve. 

We  have  on  the  other  hand  often  the  opportunity  of 
observing  circumstances  in  which  the  urine  contams  an 
excess  of  urates,  and  of  ascertaining  that  the  disturb- 
ances from  which  in  this  case  the  system  suffers  have 
sometimes  a  strong  resemblance  to  those  of  consecutive 

muscular  fatigue.  ,      ^    1  .-    c 

Attacks  of  intermittent  fever,  and  of  rheumatic  lever 
without  any  local  affections,  are  two  disorders  which 
much  resemble  the  fever  of  stiffness.  Now  these  two 
disorders  are  accompanied,  like  stiffness,  by  an  abundant 
excretion  of  urates. 

A  cold  shower-bath  taken  by  a  person  unused  to  it 
generally  produces  a  tolerably  severe  subsequent  disturb- 
ance, with  a  general  feeling  of  tenderness  in  the  limbs, 
and  slight  febrile  reaction  ;  we  have  been  able  to  assure 
ourselves  by  observations  on  the  urines  of  persons  suffer- 
ing from  these  symptoms,  which  are  so  similar  to  those 
of  .>tiffness,  that  there  is  an  abundant  deposit  of  urates. 

It  might  be  objected  that  since  in  the  examples  quoted 
there  is  a  febrile  reaction,  we  should  attribute  to  the 
fever  the  production  of  the  urates  equally  in  the  stiffness 
of  fatigue  and  in  the  attacks  of  intermittent  or  rheumatic 
fever.  °  But  fever  only  exceptionally  occurs  after  violent 
exercise,  \\'hile  we  can  frequently  observe  an  abundant 


130  PHYSIOLOGY  OF  BODILY  EXERCISE. 

deposit  of  urates  in  circumstances  in  which  muscular 
work  has  left  the  pulse  and  the  temperature  quite  normal. 
We  believe  tlie  urates  and  other  waste-products  of  com- 
bustion which  accompany  them,  to  be  the  causes  and 
not  the  effects  of  the  fever.  The  febrile  condition  in 
stiffness  results  from  an  effort  on  the  part  of  the  system 
towards  the  elimination  of  these  waste-products,  when 
they  have  accumulated  in  too  great  quantities. 

It  is  impossible  to  avoid  seeing  a  certain  analogy 
between  the  process  of  the  fever  of  stiffness  and  that 
of  an  attack  of  gout.  In  these  cases  there  is  uricaemia, 
that  is  to  say,  an  excess  of  urates  in  the  blood.  Only,  in 
the  gouty  attack  the  blood  discharges  itself  into  the 
articulations,  and  there  rejects  the  excess  of  urates,  while 
in  the  stiffness  of  fatigue  it  discharges  itself  by  means  of 
the  kidneys,  and  the  noxious  substances  are  eliminated 
in  the  urine. 

This  analogy  in  the  causes  is  confirmed  by  observa- 
tion. In  persons  predisposed  to  gout,  violent  exercise 
taken  without  preliminary  training,  is  often  the  exciting 
cause  of  an  attack.  It  is  because  the  attack  of  gout,  like 
that  of  stiffness,  is  due  to  an  accumulation  of  uric  acid 
compounds  in  the  blood,  to  a  condition  of  uricaemia. 
Too  violent  muscular  exercise  temporarily  places  the 
organism  in  all  the  conditions  necessary  for  the  explosion 
of  the  accidents  of  the  uric  acid  diathesis.  We  have 
often  observed  that  the  most  violent  exercise  is  without 
danger  for  the  gouty  person  when  he  is  in  a  condition  of 
perfect  training.  One  of  our  intimate  friends,  the  very 
active  president  of  a  fencing-club,  has  for  a  long  time 
been  subject  to  gout.  The  most  prolonged  bouts  have 
never  produced  in  him  the  least  attack  of  gout  as  long 
as  he  remained  in  training  ;  but  on  the  other  hand  he 
has  several  times  suffered  from  well  marked  arthritis 
on  resuming  fencing  after  too  long  an  absence  from  the 
school. 

If  the  condition  of  training  frees  a  gouty  person  from 
the  dangers  which  fatigue  ordinarily  has  for  him,  it  is 
because  in  the  man  in  training  work  does  not  produce 


STIFFNESS.  131 

deposits  of  urates,  nor  the  transient  condition  of  uric- 
aemia  which  causes  them. 

But  a  last  question  remains  to  be  solved  in  order 
to  ^ive  a  satisfactory  explanation  of  the  production  of 
stiffness.  Why  is  it  that  the  nitrogenous  waste- 
products  which  form  the  deposit  of  urates,  are  not 
formed,  the  work  being  equal,  in  the  man  in  training, 
just  as  in  the  man  who  performs  an  exercise  for  the  first 
time  ? 

There  can  be  but  one  answer  to  this  question,  namely, 
that  in  the  man  who  does  not  exercise  his  muscles,  there 
exist  materials  capable  of  giving  rise  to  these  products 
of  incomplete  combustion,  whereas  in  the  man  in  training 
the  muscular  work  has  used  up  these  materials,  and 
caused  them  to  disappear.  The  daily  practice  of  the 
violent  exercise  has  gradually  brought  about  the  dis- 
appearance of  the  reserve  materials  which  were  accumu- 
lated in  the  muscles.  Work  has  burned  up  and  dissi- 
pated the  materials  hoarded  by  inaction. 

The  reserve  materials  are  only  destined  to  stay  a  short 
time  in  the  system  ;  they  are  provisions  of  fuel  for  combus- 
tion, and  not  intended  to  enter  into  the  intimate  woof  of 
the  body,  and  to  become  an  integral  part  of  it.  Hence 
these  materials  are  more  easily  affected  by  the  process  of 
dissimilation.  They  resist  less  the  combustions  of  work  ; 
they  burn  more  readily,  and  are  discharged  from  the 
organs  before  undergoing  the  last  stages  of  oxidation, 
and  remain  in  the  condition  of  products  of  incomplete 
combustion.  These  waste  products,  to  follow  the  ex- 
pression  of  Bouchard,*  are  true  organic  cinders. 

The  further  we  examine  the  facts,  the  more  is  this 
opinion  confirmed. 

Amateur  gymnasts  know  well,  that,  in  resuming  an 
exercise  which  has  not  been  practised  for  a  long  time,  it 
is  imiDOssible  to  avoid  stiffness  ;  but  all  those  who  have 
had  occasion  to  go  through  this  little  trial,  know  that 
there  are  two  ways  of  paying  tribute.     One  is,  every  day 

*  Bouchara^  loc.  ciL 


Ï32  niYSIOLOGY   OF   BODILY    EXERCISE. 

to  do  a  small  amount  of  work  gradually  increased,  and 
thus  after  a  sufficient  time  to  resume  the  usual  quantity 
of  exercise.  They  feel  only  slight  discomfort  after  the 
exercise,  and  their  urine  shows  only  a  slight  cloud.  They 
come  in  time  to  the  most  violent  gymnastic  exercises 
without  ever  passing  through  the  condition  of  complete 
stiffness.  This  is  because  they  have  only  produced  every 
day  a  minimal  quantity  of  the  waste  products  of  combus- 
tion. These  waste  products  were  insufficient  to  cause 
any  serious  disturbance  in  the  system,  and  not  abundant 
enough  to  make  the  urine  very  turbid.  Others  prefer 
to  free  themselves  more  quickly  and  do  on  the  first  day 
all  the  work  they  can,  exercising  their  muscles  without 
any  stint.  There  results  on  the  following  day  severe 
stiffness  and  urine  loaded  with  urates.  But  on  the  third 
day,  usually,  they  have  recovered  all  their  fitness  for  exer- 
cise, and  are  quite  free  from  consecutive  fatigue.  From 
this  time  also  their  urine  is  free  from  deposit,  and  keeps 
perfectly  clear  after  exercise. 

These  two  different  methods  lead  in  the  end  to  the 
same  result  ;   the  using  up  of  the  reserve  materials. 

If  we  seek  to  establish  as  clearly  as  possible  the 
conclusions  to  be  drawn  from  the  facts  we  have  observed, 
and  recorded  here,  to  contribute  to  the  study  of  consecu- 
tive fatigue,  we  shall  be  led  to  formulate  two  opinions,  of 
which  one  is  an  established  fact,  and  the  other  a  very 
probable  hypothesis. 

1.  We  can  state  as  an  established  fact,  the  increase 
in  the  products  of  incomplete  combustion  which  form  the 
deposits  of  urates  in  all  cases  in  which  muscular  work  is 
followed  by  the  general  disturbances  of  stiffness,  whether 
febrile  or  not. 

2.  We  propose  as  a  probable  hypothesis  which  estab- 
lishes a  relation  of  cause  and  effect  between  these  pheno- 
mena closely  united  by  a  constant  coexistence  ;  produc- 
tion of  nitrogenous  waste-products  which  form  deposits 
of  urates,  and  appearance  of  the  general  disturbances  of 
consecutive  fatigue.  This  hypothesis  seems  to  us  founded 
on  bufficient  deduction  to  allow  us  to  attribute  the  stiff- 


STIFFNESS.  •  133 

ness  of  fatigue  to  a  kind  of  auto-intoxic^tion  of  the 
system  by  the  products  of  dissimilation. 

There  will  thus  be  a  certain  analogy  between  the  pro- 
cess of  stiffness  and  that  of  breathlessness.  These  two 
forms  of  fatigue  will  be  due  to  the  accumulation  in  the 
blood  of  certain  products  of  dissimilation. 

The  respiratory  distress  which  we  call  breathlessness 
is  due  to  the  saturation  of  the  blood  with  a  product  of 
dissimilation  which  is  eliminated  by  the  lungs.  The 
general  discomfort  which  we  call  consecutive  fatigue  or 
stiffness  of  fatigue,  must  be  attributed  to  the  presence  in 
the  economy  of  certain  products  of  dissimilation  which 
are  eliminated  by  the  kidney. 

We  know  the  product  which  causes  breathlessness  ;  it 
is  carbonic  acid. 

It  is  much  more  difficult,  in  the  present  state  of  our 
knowledge,  to  point  out  the  product  or  products  which 
are  the  true  cause  of  stiffness.  But  we  can  affirm  that 
these  products  are  found  among  the  substances  which  go 
to  form  deposits  of  urates,  and  that,  among  these,  uric 
acid  and  the  urates  play  an  important  part  in  the  pheno- 
mena of  general  consecutive  fatigue. 


CHAPTER  Vîî. 

OVERWORK. 

Overwork  is  Exaggerated  Fatigue — Different  forms  of  Overwork— 
Acute  Overwork  ;  Death  from  Breathlessness — Sub-acute  Over- 
work— The  Stag  hunted  to  Death — Forced  Game  ;  Rapid 
Cadaveric  Rigidity  ;  Prompt  Putrefaction' — Mechanism  of 
Death  by  sub-acute  Overwork — Auto-Intoxication  by  products 
of  Dissimilation — Extractives — Lactic  Acid — Discoveries  of 
Gautier  ;  Poisons  of  Living  Organisms  ;  Leucomaines — Rarity 
of  sub-acute  Overwork  in  Man — The  Soldier  of  Marathon  — 
Observations  on  rapid  Cadaveric  Rigidity  in  Men  dying  in 
a  condhion  of  Overwork  —  Curious  positions  of  the  bodies  ; 
Horror-Stricken  Expressions  in  Persons  who  have  been 
Assassinated — Effects  of  Overwork  on  the  Flesh  of  Animals — • 
Dangers  of  Eating  Overworked  Flesh — Culinary  Qualities 
given  to  Flesh  in  certain  cases  by  Overwoik — Suffering  a 
cause  of  Overwork — Cruelty  of  a  Butcher  —  Chronic  Over- 
work the  form  most  frequently  observed  in  Man. 

I. 

Overwork  is   nothing    but    fatigue    pushed    to    an 
extremity. 

We  have  seen  that  excessive  work  has  as  its  conse- 
quence the  formation  in  the  system  of  certain  products 
of  dissimilation,  and  that  the  general  disorders  of  fatigue 
are  caused  by  a  kind  of  intoxication  of  the  body  by 
these  waste-products,  the  injurious  influence  of  which  is 
felt  until  they  are  eliminated  from  the  body  by  the  excre- 
tory organs.  In  the  condition  of  overwork  the  organism 
is  no  longer  able  to  strive  against  the  too  abundant 
waste-products,  which  the  eliminating  organs  are  inca- 
pable of  removing.  There  is  a  disproportion  between 
the  eliminating  power  of  the  organism  and  the  great 
quantity  of  the  products  of  combustion  with  which  it  is 
encumbered. 


OVERWORK.  135 

Between  fatigue  and  overwork  there  is  simply  a 
difference  of  dose  in  the  substances  which  poison  the 
organism  ;  the  substances  are  the  same  and  have  the 
same  origin  ;  they  are  ahvays  the  waste-products  of 
combusrion  produced  by  work. 

A  man  who  stops  out  of  breath  after  running  for  five 
minutes  is  simply  a  man  whose  system  is  under  the 
influence  of  transient  intoxication  with  carbonic  acid 
resulting  from  exercise.  A  horse  urged  into  a  very 
rapid  gallop,  and  forced  to  run  till  it  drops,  dies  over- 
worked. The  accidents  which  kill  it  are  due  to  the 
carbonic  acid  gas  with  which  its  system  is  saturated  ;  in 
the  case  of  the  man,  the  poisonous  gas  has  been  elimi- 
nated in  time  ;  in  the  case  of  the  horse  it  has  accumulated 
in  quantity  sufficient  to  cause  death. 

Carbonic  acid  is,  of  all  the  products  of  combustion, 
that  which  is  formed  most  rapidly  and  in  largest  quantity 
during  work.  It  is  the  most  dangerous  to  the  organism; 
it  is  the  one  which  causes  the  man  and  animal  the  most 
pressing  dangers.  When  the  organism  has  the  under 
hand  in  the  contest  for  its  elimination,  the  fight  is  always 
very  short,  and  rapidly  fatal.  This  is  what  we  observe 
in  a  horse  excited  to  gallop  with  insufficient  time  to 
breathe,  we  make  it  exceed  its  paces,  that  is  to  say,  we 
demand  from  it  a  speed  out  of  proportion  to  the  power 
of  its  lungs.  The  animal  which  exceeds  its  paces,  makes 
more  carbonic  acid  than  its  lungs  can  eliminate.  In 
a  short  time  there  accumulates  in  the  blood  a  suffi- 
cient quantity  to  produce  the  first  symptoms  of  poi- 
soning. If  we  allowed  it  to  stop,  only  for  a  minute, 
it  could,  in  this  short  rest,  discharge  the  excess  of  gas 
which  distresses  it,  and  continue  its  course  without 
danger.  But  if  we  do  not  give  it  a  moment's 
breathing  space,  it  retains  this  excess  of  carbonic 
acid,  of  which  the  quantity  increases  every  moment, 
the  nerve  centres  are  supplied  with  blood  incapable 
of  maintaining  life,  the  heart-muscle  is  impregnated 
with  a  substance  which  paralyses  it,  the  circulation 
stops  and  the  animal  dies.  Death  from  breathless- 
ness    may  be    considered   as    the    type  of   acute   over- 


136  PHYSIOLOGY  OF   BODILY  EXERCISE. 

work.  This  form  of  overwork  is  really  asphyxia  from 
auto-intoxication. 

What  we  have  called  stib-aaite  overwork  has  a  less 
rapid  course.  The  type  of  this  is  furnished  by  the 
hunted  animal.  In  this  sport  the  animal  must  not 
be  killed,  but  taken,  that  is  to  say,  pursued  to  the 
extremity,  till  the  complete  exhaustion  of  its  poweis 
renders  it  unable  to  escape  the  hounds. 

We  will  study  what  happens  to  a  stag  worn  with 
fatigue  and  the  death-whoop  of  which  will  soon  be 
sounded. 

The  animal  has  been  doubling,  that  is,  instead  of  going 
straight  forward,  it  has  stopped,  and  tried  to  conceal 
itself  after  returning  for  some  distance,  after  making 
doubles  to  throw  the  dogs  off  the  scent.  Its  course  is 
thus  interrupted  by  numerous  stoppages  long  enough  to 
allow  it  to  take  breath  and  eliminate  carbonic  acid.  In 
this  manner  the  chase  may  continue  for  a  long  time, 
five  or  six  hours,  sometimes  longer,  which  would  not  be 
possible  if  it  ran  without  stopping,  for  fright  would  make 
it  exceed  its  paces,  and,  though  much  swifter  than  the 
hounds,  it  would  become  breathless,  and  quickly  be 
caught.  All  huntsmen  know  that  if  the  beast  leaves  the 
forest  to  take  a  long  run  in  the  open,  the  chase  will  soon 
come  to  an  end  ;  unless  indeed,  the  animal  be  one  of 
great  strength,  an  old  wolf  for  example,  which  laughs 
at  the  dogs,  knows  the  strength  of  its  own.  legs,  and 
does  not  do  its  hunters  the  honour  of  exceeding  its 
paces  in  the  effort  to  escape. 

The  stag  avoids  then,  by  doubling,  being  overcome  by 
breathless ness  ;  but  the  excessive  work  which  it  performs 
in  order  to  escape  from  its  enemies  gives  rise  to  various 
products  of  dissimilation,  which  after  a  time  become 
largely  accumulated  in  the  system,  for  they  cannot,  like 
carbonic  acid,  be  eliminated  in  a  few  minutes.  The 
greater  part  of  these  products  are  in  fact  eliminated  by 
the  urine,  and  we  have  already  said  that  waste-products 
eliminated  in  the  urine  are  very  slowly  discharged.  It 
will  then  be  impossible  for  the  deer  to  free  itself  during 
the  chase  from  these  products  of  combustion  with  which 


OVERWORK.  137 

its  muscles  are  loaded,  and  its  blood  poisoned.  When 
their  accumulation  becomes  excessive,  two  orders  of 
phenomena  occur.  In  the  first  place,  movements  are 
difficult  owing  to  the  disturbances  occasioned  in  the 
motor  organs  by  the  waste-products  with  which  they  are 
loaded,  and  which  we  may  compare  to  the  cinders  which 
choke  a  fire,  or  to  the  soot  which  fills  up  the  passage  of 
a  chimney.  In  the  second  place,  these  waste-products 
pass  into  the  vessels  and  are  taken  up  by  the  blood 
current,  causing  speedy  infection  of  the  system. 

After  some  hours  of  a  rapid  run,  the  deer  begins 
to  slacken  its  pace,  its  legs  become  stiff,  and  the  hounds 
gain  on  it.  It  is  on  its  last  legs  say  the  huntsmen. 
From  our  point  of  view  it  is  poisoned  by  organic 
waste-products,  the  formation  of  which  has  been 
excessive,  and  which  have  accumulated  in  great 
quantity.  Its  limbs  are  stiff  because  the  muscle-plasma 
begins  to  coagulate  under  the  influence  of  an  acid  elabo- 
rated by  the  combustions,  sarcolactic  acid,  and  because 
its  muscles  as  a  whole  have  undergone  a  true  chemical 
decomposition  under  the  influence  of  the  heat  of  work. 
The  motor  organs  of  the  animal  fail  it,  it  can  no 
longer  run,  and  lets  itself  be  taken  alive  by  the  hounds. 
But  this  is  not  the  only  cause  of  its  death  ;  for  if,  by 
a  last  double,  the  deer  succeeds  in  throwing  the  hounds 
off  the  scent,  it  generally  dies  from  the  consequences  of 
overwork. 

An  animal  thoroughly  overdriven  does  not  need  to  be 
killed  either  bv  the  hounds  or  bv  the  huntsman  ;  it 
perishes,  and  often  on  the  day  following  the  hunt  we  find  in 
the  brushwood  the  corpse  of  the  animal  which  had  escaped, 
the  hounds,  and  which  has  died  of  fatigue.  A  friend  of 
mine  had  set  free  in  his  woods  a  few  deer,  and  hunted 
them  sometimes  without  intending  to  take  them,  but 
simply  to  exercise  his  hounds,  stopping  the  chase  when- 
ever he  saw  the  animal  was  nearly  exhausted.  It 
happened  that  several  deer  died  of  the  efl'ects  of  this 
hunting,  which  was  nothing  but  a  game,  a  kind  of  sham 
fight,  in  which  the  animal  was  untouched.  It  is  not 
merely  the  inability   to   run,  the   local  fatigue   of  the 


Î^S  riIYSIOLOGY  OF   BODILY  EXERCISE. 

limbs  which  makes  up  the  condition  of  the  overdriven 
animal  ;  it  is  a  general  condition  of  decomposition  of 
the  living  tissues  capable  of  having  fatal  effects.  The 
overdriven  animal  is  one  poisoned  by  a  kind  of  putre- 
faction of  its  yet  living  flesh. 

If  we  examine  the  body  of  an  animal  hunted  to  death 
we  find  certain  phenomena  which  are  exceedingly  in- 
teresting to  study.  In  the  limbs  there  occurs  almost  in- 
stantaneously a  stiffness  known  as  cadaveric  rigidity. 
This  phenomienon  is  observed  in  all  animals  after  death, 
man  included  ;  but  it  does  not  usually  appear  till  some 
hours  after  death,  while  in  the  hunted  animal  it  occurs 
immediately  life  is  extinct,  sometimes  even  during  the 
last  moments  of  the  death-struggle.  There  is  nothing 
more  curious,  or  more  capable  of  moving  a  man  to  pity, 
if  a  hunter  is  capable  of  feeling  pity,  than  to  see  an 
unfortunate  hunted  animal  dragging  along  its  limbs 
which  it  is  unable  to  bend,  and  which  are  as  stiff  as  a  log 
of  wood. 

Cadaveric  phenomena  then  begin  a  few  moments 
before  death  in  animals  suffering  from  sub-acute  over- 
work. 

Among  the  phenomena  which  follow  death,  there  is 
one  which  comes  on  much  earlier  than  under  ordinary 
circumstances  ;  this  is  putrefaction.  The  game  hunted 
to  death  cannot  be  kept,  it  must  be  eaten  at  once,  for  it 
is  already  high  a  few  hours  after  death.  The  body  of  a 
hunted  animal  putrefies  and  decomposes  with  the  same 
raffidity  as  that  of  a  man  carried  off  by  an  infectious 
disease,  and  whose  burial  has  to  be  quickly  performed. 
Ordinarily  we  can  keep  for  a  long  time  the  body  of  an 
animal  if  we  have  removed  the  viscera  directly  after 
killing  it.  The  necessity  for  this  precaution  is  explained 
by  the  constant  presence  of  microbes  in  the  alimentary 
canal,  which  after  death  penetrate  all  the  tissues,  which 
are  no  longer  protected  from  this  action  by  vital  pro- 
cesses. In  the  hunted  game,  evisceration  is  quite  useless, 
and  does  not  retard  putrefaction.  This  is  because  the 
origin   of  this  putrefaction  is  not  an  agent  introduced 


OVERWORK.  139 

from  without,  but  is  due  to  products  which  arc  formed  in 
the  organism  during  work,  and  above  all  in  the  parts 
which  have  done  most  work,  the  muscles. 

The  rapid  corruption  undergone  by  the  body  of  the 
overworked  animal  is  caused  by  chemical  changes 
occurring  in  the  muscles.  These  muscles  are  nothing 
else  than  the  meat  or  flesh  of  the  anin^l  :  they  make  up 
more  than  half  the  body-weight,  and  it  is  not  surpris- 
ing that  a  change  in  the  composition  of  so  great  a  mass 
can  have  very  marked  effects  on  the  whole  organism. 

Muscles  which  have  worked  to  excess,  have  undergone 
a  change  in  their  chemical  composition.  Alkaline  in  a 
state  of  repose,  they  have  become  acid  :  they  contain 
lactic  acid  which  was  not  present  before  work  ;  they 
contain  less  oxygen  and  more  carbonic  acid  than  when 
at  rest.  Numerous  nitrogenous  materials  resulting  from 
the  combustion  of  muscular  tissues  are  considerably 
increased. 

These  substances,  of  which  the  last  stage  of  combus- 
tion is  urea,  form  a  series  of  bodies  only  differing  in 
containing  m^ore  or  less  oxygen,  and  being  consequently 
at  a  different  degree  of  oxidation  or  combustion.  All 
authors  enumerate  amongst  them  kreatin,  hypoxan- 
thin,  inosit,  etc.,  and  finally  the  best  known  one,  and  the 
most  interesting  because  of  the  part  it  plays  in  the  pro- 
duction of  gout,  uric  acid. 

These  substances  generally  crystallise  with  difficulty, 
and  have  the  common  character  of  dissolving  in  alcohol 
when  a  fatigued  muscle  is  macerated  in  this  liquid.  They 
are  generally  called  extractives. 

Extractives  are  found  in  muscle  in  a  condition  of  rest, 
but  in  much  greater  quantity  in  a  condition  of  overwork. 
Liebig  was  able  to  extract  ten  times  as  much  kreatin 
from  the  muscles  of  a  hunted  fox  as  from  those  of  an 
animal  killed  after  confinement  in  a  cage  in  the 
laboratory. 

What  is  the  part  played  by  these  extractives  in  the 
production  of  overwork  ?  Have  they  the  principal 
share  in   the  production  of  the  phenomena  observed  in 


I40  PHYSIOLOGY  OF   BODILY   EXERCISE. 

overworked  animals?  These  are  questions  to  which  we 
can  g-ive  a  satisfactory  answer.  Gautier  (Académie  de 
Médecine,  15th  January,  1886),  has  shown  that,  amongst 
the  products  of  muscular  work,  there  are  formed  alkaloids 
of  a  toxic  power  not  inferior  to  that  of  the  poisons  already 
d {^.covered  in  putrefied  flesh,  and  known  as  ptomaines. 
It  is  impossible,  in  the  present  state  of  science,  to  give 
the  names  and  the  chemical  characters  of  the  organic 
substances  which  are  the  true  causes  of  the  phenomena 
of  overwork,  but  everything  leads  to  the  belief  that  these 
alkaloids,  called  by  Gautier  leucomaïnes,  are  the  cause  of 
most  of  the  accidents,  still  but  ill  understood,  from  which 
overworked  animals  and  men  suffer. 

In  man  it  is  rare  to  observe  cases  of  sub-acute  over- 
work, especially  in  our  stage  of  civilization.  Antiquity 
records  a  celebrated  example  of  it,  that  of  the  soldier  of 
Marathon  who,  wishing  to  be  the  first  to  bring  news  of 
the  victory,  ran  to  Athens  without  stopping  and  fell  dead 
on  arrival. 

We  can  assure  ourselves  that  fatigue  carried  to  its 
utmost  limits  brings  about,  in  man  as  in  other  animals, 
the  speedy  advent  of  rigidity  of  the  whole  muscular 
system.  Combatants,  dead  after  a  long  and  bloody 
contest,  whose  bodies  were  in  the  condition  of  sub-acute 
overwork,  have  been  seen  to  preserve  strange  positions. 
Their  corpses  have  remained  in  the  positions  correspond- 
ing to  the  movements  of  attack  and  defence.  Cada\eric 
rigidity  coming  on  in  the  very  moment  of  death,  had 
surprised  the  dying  men  in  their  last  attitudes,  and  the 
muscles,  instantaneously  stiffening,  had  preserved  them. 

Under  the  influence  of  sub-acute  overwork  cadaveric 
rigidity  invades  as  rapidly  the  muscles  of  the  face  as 
those  of  the  rest  of  the  body,  and,  for  the  same  reason, 
may  keep  these  muscles  in  the  contraction  in  which  they 
were  in  the  last  moments  of  life,  and  consequently  pre- 
serve the  expression  of  the  last  emotions  experienced.  In 
persons  who  have  been  assassinated,  and  who,  endeavour- 
ing to  defend  themselves,  have  been  engaged  for  some 
minutes   in  a  supreme    struggle,  there    has   sometimes 


OVERWORK.  141 

been  seen  an  expression  of  terror  lasting  for  some  hours 
after  death.  Their  despairing  efforts  to  escape  their 
murderers  had  occasioned  rapid  overwork  :  rigidity  ot 
the  facial  muscles,  coming  on  very  quickly,  had  as  it 
were,  stereotyped  the  last  expression. 

If  it  seems  surprising  that  cadaveric  rigidity  should 
occur  in  the  very  moment  of  death,  we  might  quote  a 
fact  recorded  by  Richet,  who  saw  the  muscles  stiffen 
before  the  heart  had  ceased  beating.* 

The  bad  effects  of  overwork  on  the  flesh  of  animals 
has  been  frequently  pointed  out  by  veterinary  surgeons, 
and  by  persons  whose  business  is  with  the  preservation 
of  meat.  The  flesh  of  animals  killed  during  great 
fatigue  becomes  quickly  flabby  and  damp  ;  it  has  a 
sour  smell,  like  that  of  dirty  linen,  according  to  the  ex- 
pression of  Raillet  and  Vilain  ;  it  is  impossible  to  keep 
it  long.  It  is  dangerous  to  use  the  flesh  of  animals 
suffering  from  overwork  unless  it  be  eaten  very  fresh. 
Epidemics  of  typhus  have  been  recorded,  due  to  the 
eating  of  animals  exhausted  by  following  armies  on  the 
march.  These  facts  are  Avell-known  in  meat-preserving 
factories,  and  in  these  industries,  precautions  are  taken 
to  prevent  the  ill-effects  of  fatigue  on  animals  to  be 
slaughtered.  In  the  saladeros  of  South  America,  great 
care  is  taken  not  to  kill  the  nearly  wild  oxen  which 
have  been  driven  a  long  distance  from  the  Pampas  to 
the  slaughter  house.  Each  establishment  is  provided 
with  a  great  court  in  which  the  animals  rest  before  being 
killed.  Their  flesh  would  not  keep  if  the  overvv^orked 
oxen  were  killed  before  two  or  three  days'  repose  had 
enabled  them  to  eliminate  the  waste-products  of  fatigue 
accumulated  in  their  blood  and  muscles. 

In  opposition  to  these  phenomena,  in  which  overwork 
gives  to  flesh  harmful  properties,  we  could  quote  others 
in  which  fatigue  is,  on  the  contrary,  desired,  as  a  means 
of  developing  peculiar  culinary  qualities  in  the  flesh  of 
animals  to  be  killed.  We  have  heard  gourmets  com- 
plain that  formerly  they  used  to  get  much  better  beef 

*  Richet.     Les  Muscles  et  les  Nerfs. 
11 


1^2  PHYSIOLOGY  OF   P.  3DILY  EXERCISE. 

than  at  the  present  time.  Before  the  days  of  rail- 
roads, the  animals  used  to  come  on  foot  by  short  stages, 
sometimes  as  much  as  a  hundred  leagues,  before  reaching 
the  slaughter  house.  It  was  said  that  the  fatigue  of 
the  journey  made  the  meat  more  tender,  and  gave  to' 
it  a  taste  of  "  hazel  nut."  Similarly,  in  South  Italy,  it  is 
usual,  before  killing  the  oxen,  which  run  almost  wild, 
and  the  flesh  of  which  is  tough  and  waxy,  to  chase 
them  for  some  time  on  horseback,  making  them  gallop 
as  fast  as  possible.  Their  flesh  acquires,  it  is  said,  after 
these  mad  gallops,  a  more  savoury  taste. 

These  facts  are  not  in  contradiction  to  those  given 
above.  They  all  alike  show  that  fatigue  causes  an 
accumulation  within  the  muscles  of  new  products,  the 
presence  of  which  profoundly  changes  the  qualities  of 
the  flesh.  If  these  products  are  not  present  in  too  great 
quantity,  and  more  especially  if  the  animal  is  eaten  soon 
after  it  is  killed,  so  as  to  avoid  the  putrefactive  fermen- 
tation which  would  quickly  come  on,  the  fatigued  flesh 
is  not  offensive.  The  extractives  even  cause  a  kind  of 
seasoning  of  the  meat,  and  give  it  a  suspicion  of  a  high 
taste,  a  flavour  agreeable  to  the  palate.  Connoisseurs 
prefer  this  savour  to  that  of  ordinary  meat,  just  as  they 
like  to  eat  their  game  high. 

It  is  always  through  overwork  that  we  can  explain 
the  peculiar  taste  of  the  flesh  of  animals  which  have 
suffered  before  death.  A  butcher  near  Limoges  had 
the  reputation  of  selling  much  better  pork  than  others 
in  the  district.  The  brute  never  killed  the  animals 
without  torturing  them.  He  pierced  their  eyes  and 
bled  them  slowly  to  death  with  small  stabs.  In  certain 
districts  in  the  South  of  France,  geese  are  only  killed 
after  being  plucked  alive,  that  their  flesh  may  be  made 
more  tender  by  suffering. 

These  abominable  practices  deserve  nothing  but 
censure  from  humane  persons,  but  we  must  recognize, 
from  the  scientific  stand-point,  that  the  idea  under  which 
they  are  performed  is  not  without  foundation.  The 
flesh  of  an  animal  which  has  suffered  extreme  pain 
may  have  a  peculiar  flavour  like  that  of  an  overworked 


OVERWORK.  143 

animal,  for  the  pain  induces  overwork.  The  unfortunate 
animal  which  is  being  tortured,  exhausts  itself  in  des- 
perate efforts  to  escape  the  pain,  and  expends  in  a  few 
minutes  as  much  nervous  energy  as  it  would  in  a  very- 
long  period  of  muscular  exercise. 

It  has  long  been  noticed  that  animals  which  have 
undergone  vivisection,  for  the  sake  of  physiological 
research,  and  which  only  die  after  suffering  for  some 
time,  and  striving  in  vain  to  escape  from  the  constant 
pain,  have  after  death  all  the  appearances  of  overworked 
animals  ;  hair  bristling,  bathed  in  sweat,  rapid  cadaveric 
rigidity,  and  flesh  subject  to  early  putrefaction. 

Here  are  phenomena  which  are  at  first  sight  very 
distinct,  and  which  we  should  not  perhaps  have  ex- 
pected to  find  in  the  same  group.  They  have,  as  we 
hope  we  have  shown,  a  common  bond,  the  formation 
within  the  organism  of  certain  products  of  dissimilation 
which  result  from  the  performance  of  an  excessive 
quantity  of  muscular  work.  These  products  are  found 
alike  in  the  body  of  the  man  muscularly  overworked, 
and  in  that  of  the  animal  which  for  a  long  time  has 
striven  against  pain,  for  in  both  cases  there  is  the  same 
excess  of  fatigue. 

Chronic  overwork  is  due,  like  sub-acute  overwork,  to 
the  impregnation  of  the  system  with  the  waste-products 
of  work  ;  but  the  course  is  not  so  rapid,  and  the  ter- 
mination usually  less  fatal,  because  the  dose  of  the 
poisonous  substances  is  less  considerable,  the  exercise 
producing  them  being  less  violent. 

This  condition  is  observed  in  persons  whose  bodies 
are  subjected  to  work  too  long  sustained,  or  to  fatigue 
too  often  repeated,  and  not  followed  by  sufficiently  long 
periods  of  repose. 

Let  us  suppose  that  a  man  ^performs  a  fatiguing  work 
which  does  not  absolutely  pass  beyond  the  measure  of 
his  powers.  The  work  is  borne,  and  produces  in  his 
system  the  ordinary  disturbances  of  consecutive  fatigue 
and  of  stifi'ness.     If  he  performs  the  same  work  on  the 


144  PHYSIOLOGY  OF   BODILY  EXERCISE. 

following  day,  the  waste-products  of  the  day  before 
have  not  been  all  eliminated  when  other  waste-products 
are  formed  and  add  to  the  last,  increasing  the  dose. 

Let  us  suppose  that  on  the  following  days  the  work  is 
again  repeated;  the  quantity  of  injurious  substances 
accumulated  in  the  blood  will  increase  more  and  more, 
and  will  reach  after  a  time  a  proportion  great  enough  to 
have  serious  consequences.  Then  the  fatigue  will  assume 
the  character  of  an  illness,  and  the  condition  of  overwork 
will  be  established. 

The  condition  of  chronic  overwork  terminates  in 
diseases  of  long  duration,  or  at  least  ill-defined  morbid 
states  which  do  not,  strictly  speaking,  constitute  diseases, 
but  which  cause  a  profound  change  in  the  organism, 
which  makes  it  liable  to  the  most  serious  consequences 
from  slight  disturbances  of  health  accidentally  produced. 
The  organism  infected  by  the  products  of  dissimilation 
becomes  an  admirable  field  for  the  hatching  of  the  most 
pernicious  germs. 

The  more  or  less  lasting  disturbances  of  health  which 
are  a  consequence  of  excessive  work  will  be  studied  in 
the  following  chapter. 


CHAPTER  VI rî. 
OVERWORK  {continued). 

The  Disorders  of  Overwork — Pseiido-Typhoid  Fevers — Auto- 
I)ifectio7i  and  Auto-  TypJiisatio?i — Opinion  of  Professor  Peter — 
Microbes  and  Leucomaïnes — -Frequency  of  Fevers  of  Over- 
work— Greater  predisposition  of  Adolescents — Two  personal 
Observations — x^buse  of  Fencing  and  too  much  of  the  Trapeze 
- — Overwork  in  the  Army — Too  Energetic  a  Colonel — Forced 
Manoeuvres  —  Overwork  a  cause  aggravating  Disease  —  In- 
fective forms  assumed  by  the  mildest  Disorders  in  Overworked 
systems — So-called  Su7i'siroke  of  Soldiers  on  the  March — The 
large  influence  of  Overwork  in  the  production  of  these  Dis- 
orders— Rarity  of  Sunstroke  in  Horse- Soldiers  ;  its  frequency 
in  Foot-Soldiers — Spares  persons  habituated  to  Fatigue — 
Rarity  of  Sunstroke  in  Harvestmen, 

It  often  happens  that  the  medical  man  is  confronted  by 
a  continued  fever  for  which  he  can  find  no  external 
cause.  No  contagion,  no  epidemic  to  invoke  :  the  case 
is  an  isolated  one.  He  is  tempted  to  diagnose  typhoid 
fever,  but  none  of  the  usual  aetiological  elements  of  this 
fever  are  discoverable  ;  a  careful  inquiry  shows  that 
there  could  have  been  no  infection  from  air,  from  water, 
from  milk,  from  a  privy  :  no  cause  of  illnesG  is  found  in 
the  persons  or  things  surrounding  the  patient.  If  then 
he  carefully  examines  the  circumstances  which  have 
preceded  the  illness,  he  will  almost  always  find  that 
his  patient  has  undergone  an  abuse  of  exercise  or  some 
excess  of  work. 

There  exists,  in  fact,  a  fever  of  overwork  which  has 
the  closest  analogy  with  typhoid  diseases,  and  amidst 
the  confusion  which  reigns  between  the  true  typhoid 
fever  and   the  serious  accidents  of  fatigue,  it  is  difficult 


14^  PHYSIOLOGY  OF   BODILY  EXERCISE. 

very  precisely  to  determine  the  pathognomonic  cha- 
racters belonging  to  the  one  and  to  the  other. 

The  fever  of  overwork  is  merely  an  exaggeration  of 
stiffness.  The  causes  and  the  processes  are  the  same. 
These  two  disorders  are  due  to  an  auto-infection,  to  a 
poisoning  of  .the  body  by  the  body  ;  and  the  infective 
agents  are,  in  both  cases,  products  of  dissimilation  due 
to  work  ;  but  in  simple  stiffness,  the  disorder  is  checked 
in  time,  and  it  has  been  possible,  thanks  to  rest,  to  elimi- 
nate the  substances  which  are  doing  the  mischief,  whereas 
in  the  fever  of  overwork  these  substances  have  been  re- 
newed by  new  work  before  they  have  been  completely 
expelled,  and  have  thus  accumulated  in -the  blood  in 
excessive  quantity. 

Overwork  does  not  always  lead  to  a  febrile  condition 
of  a  typhoid  character.  It  often  happens  that  the 
disorder  is  limited  to  a  condition  of  general  prostration, 
to  a  languor  of  all  the  functions.  In  this  case  there 
is  no  explosion,  and  the  disturbances  of  the  system 
are  checked  in  the  prodromal  stage,  in  the  condition 
when  disease  is  imminent.  It  is  a  menace  which 
aborts,  because  the  abuses. which  have  called  it  forth 
are  remedied  in  time.  The  disorder  which  was 
smouldering  did  not  burst  into  flame,  because  the 
organism  was  placed  in  better  hygienic  conditions — and 
the  only  efficient  hygienic  condition  against  overwork, 
is  repose.  It  is  thus  that  we  must  explain  many 
morbid  conditions  known  as  abortive  typhoid  fever^  in 
which  symptoms  of  great  severity  sometimes  develop 
and  disappear  in  a  few  days. 

Overwork  is  usually  quoted  among  the  predisposing 
causes  of  typhoid  fever  ;  but  overwork  is  much  more 
than  a  predisposing  cause  of  typhoid  fever  ;  it  is  capable, 
in  absence  of  all  other  causes,  of  producing  epidemics 
of  continued  fever  absolutely  resembling  typhoid  fever. 

Sevrael  eminent  members  of  the  Academy  of  Medicine, 
in  a  most  interesting  discussion  {Comptes  rendus,  March, 
1886),  on  the  subject  of  the  poisons  discovered  by 
Gautier  as  the  products  of  living  organisms,  have  drawn 
attention    to    the    importance    of    auto-intoxication   in 


OVERWORIC  147 

disease.  They  showed  that  the  blood  can  suffer  from  the 
toxic  influence  of  certain  chemical  poisons  called  leuco- 
maines  which  are  elaborated  in  the  organism  itself,  and 
accumulate  in  it  in  certain  cases,  whether  it  be  owing  to 
defective  elimination  or  to  excessive  production.  Pro- 
fessor Peter  calls  this  mode  of  infection  aiito-typJiisation, 
because  it  gives  rise  to  affections  quite  similar  to  those 
of  the  typhoid  disorders. 

Excessive  work,  an  active  cause  of  the  accumulation 
of  organic  poisonous  substances,  often  terminates  in 
auto-typhisation. 

We  have  been  able  personally  to  observe  several 
cases  of  these  pseudo-typhoid  fevers,  in  persons  whose 
mode  of  life  was  well-known  to  us.  We  could  easily 
proceed  from  the  effect  to  the  cause,  and  recognise, 
after  careful  inquiry,  the  exclusive  share  which  excessive 
muscular  work  had  in  the  production  of  the  disorder. 

We  were  specially  struck  by  two  of  the  cases.  One 
man  w^as  overworked  by  fencing,  spending  six  hours 
daily  with  the  foil  in  his  hand.  Another  had  over- 
done his  gymnastics  and  exercised  four  hours  daily 
on  a  horizontal  bar  at  his  own  house.  Both  were 
adolescents,  and  at  this  age,  the  anatomical  elements 
of  the  body,  less  stable  than  in  the  adult,  more  easily 
undergo  dissimilation.  The  work  had  acted  on  their 
tissues,  and  the  superabundant  waste-products  resulting 
from  too  intense  combustions  had  poisoned  their 
systems. 

Constantly  in  practice  the  physician  meets  with  cases 
which  puzzle  him,  and  which  would  be  inexplicable  if 
overwork  were  not  invoked  as  the  cause  of  the  pheno- 
mena. A  barrack  is  old  ;  the  w^alls  and  floors  doubtless 
contain  microbes,  for  an  epidemic  occurs,  and  typhoid 
fever  decimates  the  men.  We  whitewash  and  we  dis- 
infect, the  epidemic  goes  on  increasing.  There  comes 
a  new  colonel  :  the  disease  disappeors  as  if  by  enchant- 
ment. This  is  because  there  is  a  less  energetic  man 
in  command.  No  more  thirty  mile  marches,  no  more 
displays  of  skill    in    gymnastics    and   vaulting  for    the 


I4S  PHYSIOLOGY  OF   BODILY   EXERCISE. 

admiration  of  the  civil  population.  The  soldier,  doing 
now  nothing-  beyond  strictly  regimental  work,  no  longer 
suffers  from  overwork  ;  diminution  of  fatigue  has  sufficed 
to  extinguish  the  epidemic. 

Typhoid  fevers,  so  frequent  in  the  army,  are  almost 
always  fevers  of  overwork.  They  are  specially  observed 
in  troops  going  through  supplementary  manoeuvres  and 
making  forced  marches.  They  are  especially  severe  on 
the  men  who  have  most  work  to  do,  in  the  artiller}^,  for 
instance,  as  happened  at  Angouleme  and  at  Clermont. 
Finally  they  attack  by  preference  young  soldiers,  who 
are  not  yet  accustomed  to  fatigue.  Further,  and  this  is 
a  characteristic  feature,  they  rarely  spread  to  the  civil 
population  in  the  houses  adjoining  the  barracks,  who  are 
not  subjected  to  the  same  causes  of  overwork. 

Many  things  prove  the  important  part  played  by 
muscular  fatigue  in  the  production  of  illness.  Many 
things  point,  by  the  side  of  external  influences,  to  the 
power  of  morbific  agents  which  arise  within  the  organism. 
Microbes,  parasitic  organisms,  play  their  part  in  the 
production  of  infectious  disorders,  but  besides  them  we 
have  to  reckon  as  causes  of  serious  disorders  certain 
chemical  poisons  which  are  developed  during  the  vital 
actions  accompanying  violent  exercise. 

These  poisons,  which  have  not  long  been  known,  and 
which  resem.ble  the  alkaloids  of  putrefaction,  are  capable 
of  exercising  a  pernicious  influence  on  the  organism 
within  which  they  are  formed,  and  by  which  they  have 
not  been  eliminated  with  sufficient  speed.  They  cause 
the  development  of  certain  forms  of  typhoid  affections. 
They  also  cause  a  remarkable  aggravation  of  the  simplest 
lesions,  of  the  most  benign  affections,  when  these  occur 
in  an  overworked  man. 

After  great  physical  fatigue,  an  attack  of  pneumonia 
or  erysipelas  assumes  an  infective  character,  and  insigni- 
ficant wounds  are  liable  to  be  complicated  by  the  acci- 
dents of  septicœmia.  It  is  no  longer  a  germ  introduced 
from  without  which  has  vitiated  the  blood  ;  it  is  the 
orgcinism  which  has  poisoned  itself  with  products  of  its 
own  manufacture.     The  illness,  which  was  at  first  benign 


OVERWORK  149 

tends  to  become  aggravated  and  to  take  on  an  infective 
form,  because  it  takes  root  in  a  field  vitiated  by  leuco- 
maines  and  other  poisons  formed  by  the  exaggerated 
activity  of  the  organs. 

Typhoid  fever  is,  according  to  all  observers,  the  result 
of  the  absorption  of  a  human  miasma.  It  always  occurs 
where  men  are  much  crowded  together.  A  celebrated 
authority,  Griesinger,*  has  pointed  out  the  remarkable 
aetiological  contrast  between  intermittent  malarial  fever, 
which  occurs  away  from  towns,  in  uncultivated  districts 
and  in  countries  in  which  men  are  few  and  vegetation 
abundant,  and  typhoid  fever,  which  occurs  in  towns  and 
in  places  encumbered  with  human  beings. 

Overwork  increases  the  dangers  of  overcrowding  by  a 
very  simple  mechanism,  by  increasing  the  quantity  of  the 
miasma  discharged  by  men  living  in  a  confined  space. 

A  dormitory  occupied  by  forty  men,  who  have  just 
made  a  forced  march,  is  much  more  charged  with  miasma 
than  one  in  which  an  equal  number  of  men,  who  have  not 
performed  any  muscular  work,  are  sleeping.  It  is  enough, 
if  we  would  be  certain  of  this,  to  go  into  a  barrack 
room  on  the  morning  after  a  long  march.  There  is 
a  very  peculiar  and  repulsive  odour  which  is  almost  un- 
bearable. NotVv^ithstanding  all  the  jokes  made  at  the  ex- 
pense of  the  foot-soldier,  it  is  not  the  feet  of  fatigued 
men  from  which  this  pestilential  odour  arises,  but  from 
their  lunchs  and  fromi  the  whole  surface  of  their  skin. 

There  have  been  many  opportunities  of  observing  facts 
which  agree  with  this  opinion  of  the  poisoning  of  man 
by  man,  and  of  seeing  that  these  intoxications  by  the 
human  miasma  are  the  more  serious,  the  greater  the 
fatigue  endured  by  the  persons  producing  the  toxic  sub- 
stance has  been. 

We  read  in  the  history  of  the  Indian  ^lutiny  the  fol- 
lowing fact  : — • 

A  regiment  of  Sepoys,  after  being  defeated  by  the 
English,  took  to  flight,  and  the  800  men  who  survived 
were  hunted  down  like  wild  beasts  during  three  days. 

*  Griesinger  y  Maladies  Infectieuses. 


I  so  PHYSIOLOGY  OF   BODILY   EXERCISE. 

Being  utterly  fatigued,  the  unfortunate  men  took  refuge 
in  a  small  island,  where  they  allowed  themselves  to  be 
taken  without  resistance,  like  hunted  animals.  After 
their  capture,  i8o  of  them  were  confined  in  a  small  room 
to  wait  until  they  were  shot.  The  following  morning, 
when  they  were  to  be  led  out  to  execution,  three-fourths 
of  them  were  dead.  The  confinement  of  these  over- 
worked men  in  too  small  a  space  had  caused  the  accu- 
mulation in  the  air  of  the  dungeon  of  a  great  quantity 
of  miasma,  the  absorption  of  which  had  caused  the  death 
of  135  of  the  prisoners.  The  45  remaining  suffered  from 
febrile  disorders  of  a  typhoid  character,  and  most  of  them 
died  after  thirty  or  forty  days'  illness. 

It  is,  moreover,  to  overwork  that  we  must  attribute  the 
greater  number  of  certain  disorders  which  are  generally 
referred  to  the  heat  of  the  sun,  and  wrongly  called  Siin- 
stT-oke. 

In  a  military  column  marching  on  a  very  hot  day,  men 
are  often  seen  suddenly  to  fall  unconscious,  and  some- 
times to  die  on  the  spot.  These  serious  attacks  are 
usually  attributed  to  the  heat  of  the  sun.  We  believe 
that  two  factors  are  needed  to  produce  the  sunstroke 
from  which  a  youns^  soldier  suffers  when  marching  under 
an  August  sun.  The  sun  is  certainly  one  of  the  factors,  but 
work  is  the  other,  and  much  the  most  important  of  the  two. 

Let  us  recall  how  the  body  relieves  itself  of  the  excess 
of  heat  developed  in  it  by  muscular  work.  We  know 
that  the  vaso-motor  apparatus  sends  more  blood  to  the 
skin  in  proportion  as  the  blood  is  heated  by  work  ;  the 
body  thus  cools  by  radiation  with  a  rapidity  in  propor- 
tion to  the  difference  between  the  temperature  of  the 
surface  of  the  body  and  that  of  the  surrounding  medium, 
this  medium  being  supposed  the  cooler  of  the  two,  as  is 
always  the  case  in  temperate  climates.  If  the  surround- 
ing air  is  much  cooler  than  the  body,  the  blood  in  passing 
through  the  skin  becomes  almost  instantaneously  cooled. 
If,  on  the  contrary,  the  external  temperature  is  higher 
than  that  of  the  body,  the  cutaneous  surface  should  gain 
instead  of  losing  heat  by  radiation. 


OVERWORK.  151 

în  spite  of  this  result,  so  unfavourable  to  the  cooHng  of 
the  blood,  the  body,  in  a  state  of  rest,  can  easily  defend 
itself  from  invasion  by  external  heat,  thanks  to  the  cool- 
ing produced  by  the  evaporation  of  sweat  from  the  skin, 
and  the  transpiration  of  vapour  by  the  lungs  ;  it  is  foi 
this  reason  that  it  is  possible,  without  any  serious  conse- 
quences, to  spend  some  minutes  in  an  oven,  the  tempera- 
ture of  which  greatly  exceeds  that  of  the  air  in  the  hottest 
summer.  But  if  to  the  action  of  the  high  temperature 
there  is  added  that  of  muscular  work,  the  organism  has 
not  only  to  fight  against  the  heat  of  the  surrounding 
medium,  it  has  also  to  defend  itself  against  the  increased 
heat  developed  in  its  own  organs.  It  is  deprived,  in  this 
unequal  contest,  of  the  assistance  of  the  vaso-motor  appa- 
ratus, the  action  of  which  has  become  useless.  The  blood, 
constantly  carried  to  the  skin,  can  no  longer  lose  heat  by 
radiation  in  a  medium  already  hotter  than  itself,  and  re- 
turns to  the  internal  organs,  carr}-ing  with  it  almost  all 
the  heat  produced  by  work. 

There  is  a  very  clear  distinction  between  our  way  of 
understanding  sunstroke  and  that  in  which  it  is  ordi- 
narily explained.  We  do  not  believe  that  the  sun  kills  a 
man  by  giving  him  more  heat,  but  simply  by  preventing 
him  from  getting  rid  of  the  internal  heat,  w^hich  is  being 
produced  in  excess.  The  practical  importance  of  this 
distinction  is  at  once  evident.  A  man  who  succumbs 
during  a  forced  march,  under  a  hot  sun,  is  not  killed  by 
the  sun,  but  by  the. forced  march.  He  does  not  die  of 
sunstroke,  but  of  overwork,  and  consequently  if  he  were 
not  overworked,  the  sun  alone  could  not  kill  him.  The 
sun  is  not  the  essential  cause  of  the  accident,  it  is  merely 
an  accessory  condition. 

In  our  temperate  climates  we  never  see  cases  of  fatal 
sunstroke  in  men  exposed  to  the  heat  of  the  sun,  unless 
these  men  have  been  doing  some  fatiguing  work.  A 
man  under  the  powerful  sun  of  July  may  perhaps  have  a 
sunstroke,  if  his  skin  is  delicate  ;  he  may  have  a  conges- 
tion of  the  brain  if  his  head-covering  is  not  sufficient  ;  he 
may  suffer  from  very  various  disorders  due  to  the  exces- 
sive heat  :    a  fainting   fit,  an   attack  of  indigestion,  etc, 


152  PHYSIOLOGY  OF  BODILY  EXERCISE. 

but  never  from  any  fatal  illness,  unless  there  be  compli- 
cation with  some  other  disease,  or  some  constitutional 
vice,  which  will  have  no  connection  with  sunstroke  pro- 
perly so  called. 

Cavalry  officers  know  that  their  men  are  rarely 
attacked  by  sunstroke,  while  the  horses  which  carry 
them  often  succumb  to  it.  It  is  among  the  infantry 
that  sunstroke  is  almost  exclusively  observed,  especially 
in  forced  marches  and  when  the  men  are  heavily  laden. 
The  infantry  officer,  who  carries  no  baggage,  is  much 
more  rarely  attacked  than  his  men,  and  among  the  latter 
the  so-called  sunstroke  always  fixes  on  those  who  are 
least  accustomed  to  fatigue.  In  the  cases  of  sunstroke 
reported  every  year  in  connection  with  the  great 
manoeuvres,  the  soldiers  who  succumb  are  always 
reserve  men  who  have  passed  without  preparation  from 
muscular  inaction  to  excessive  work,  and  are  placed,  in 
consequence,  in  the  conditions  most  favourable  for  the 
production  of  overwork. 

The  same  observations  have  been  many  times  made 
as  regards  animals.  It  is  a  matter  of  common  notoriety 
that  horses  are  so  much  the  more  liable  to  sunstroke, 
the  fatter  they  are,  and  the  less  trained  by  daily  work. 

Men  inufed  to  fatigue,  those  who  daily  do  hard  work, 
rarely  suffer  in  the  way  we  have  just  described.  We 
never  see  in  the  country  a  peasant  die  of  sunstroke. 
And  yet  no  regiment  performing  manœuvres  ever 
supports  the  heat  of  the  sun  longer  and  with  as  much 
disregard  of  precaution  as  do  the  reapers. 

To  sum  up,  the  heat  of  the  sun  cannot  alone  cause 
death,  except  in  tropical  climates.  The  cases  of  so- 
called  sunstroke  seen  in  our  temperate  countries  are 
indeed  due  to  an  increase  in  the  temperature  of  the 
blood,  for  a  temperature  of  112°  F.  has  been  noticed  in 
dying  persons  ;  but  this  excessive  temperature  is  not 
the  result  of  the  heat  of  the  sun,  it  is  a  consequence  of 
excessive  vital  combustion. 

What  kills  a  man  in  so-called  sunstroke  is  overwork, 
from  which  he  suffers  in  ill-understood  hygienic  con- 
ditions, but  it  is  not  the  sun. 


CHAPTER   IX. 
OVERWORK  {concluded), 

A  Phthisical  Hercules — The  Overtrained  Horse — Chronic  Over- 
work— Exhaustion  through  using  up  of  the  Organic  Tissues 
^Difference  between  the  Physiological  Processes  of  Acute 
and  of  Chronic  Overwork — Auto-hitoxication  and  Autophagy — 
Dangers  of  excessive  Expenditure — Defective  Balance  between 
Expenditure  and  Income — Impoverishment  of  the  System  by 
excessive  work — Atrophy  and  Degeneration  of  Muscles — The 
Calves  of  Runners — Overwork  of  the  Heart- Muscle — The 
Over-D?'iven  Heart — Nervous  Forms  of  Overwork — Anaemia 
of  the  Nerve-Centres  and  Exhaustion  of  the  Nervous  Substance 
— Epilepsy  of  Walkers — Observations  on  Peasants — Insanity 
from  Overwork  ;  Influence  of  Harvest-Tmie  on  its  Frequency — 
Frequency  of  Neuroses  in  Overworked  Peasants. 

One  day,  passing  before  a  booth  of  acrobats,  we  were 
struck  by  the  sickly  appearance  of  a  man  who  was 
haranguing  the  crowd,  and  all  the  while  juggling  with 
cannon-balls  and  dumb-bells.  He  was  a  great,  raw- 
boned  fellow,  with  a  starved  appearance,  drawn  features, 
long  and  slender  limbs,  but  none  the  less  seeming  to 
have  great  muscular  strength,  to  judge  from  the  ease 
with  which  he  handled  his  weights. 

The  booth  was  a  wretched  one,  and  the  spectators  far 
from  choice,  but  the  desire  of  seeing  at  work  tni.'i 
Hercules  of  phthisical  build  overcame  our  self-respect, 
and  going  up  the  inclined  plank  which  took  the  place  oi 
a  staircase,  we  entered  the  establishment. 

Then  we  could  see  the  man  more  closely  and  assure 
ourselves  that  his  limbs,  in  spite  of  the  strength  showrj 
by  his  performances,  were  thin  and  fleshless.  His  thin 
thighs,  which  worked  wonders  in  French  boxing,  no 
longer  filled  his  tights,  which  fell  in  numerous  folds. 
Finally  a  weak  and  hoarse  voice,  with   a  few    fits   of 


154  PHYSIOLOGY  OF   BODILY  EXERCISE. 

coughing,  made  us  believe  that  this  strong  man  had  an 
extremely  delicate  chest. 

When  the  performance  was  over,  we  found  it  easy  to 
become  initiated  into  the  mode  of  life  of  this  man  who 
seemed  to  us  an  interesting  case  for  study.  Hurrying 
from  fair  to  fair  he  worked  excessively  hard,  giving  ten 
performances  a  day,  in  each  of  which  he  had  to  throw 
one  or  two  opponents,  not  to  speak  of  single-stick, 
French  boxing,  and  juggling  with  weights  and  dumb- 
bells. I  His  muscles  were  rarely  idle,  but  they  did  not 
increase  in  size,  far  from  it.  It  is  true  that  his  diet  was 
not  fattening,  and  he  only  dined  well  when  the  takings 
were  good.  The  strong  man,  becoming  more  confiding, 
spoke  to  us  about  his  health,  and  we  could  easily 
understand  that  he  was  phthisical.  In  fact,  shortly  after- 
wards we  heard  that  he  had  fallen  a  victim  to  pulmonary 
phthisis. 

Such  is  often  the  end  of  strong  men,  who,  beginning 
by  mastering  fatigue,  after  going  through  a  training 
which  enables  them  to  work  to  excess  without  feeling 
the  discomfort  of  fatigue,  exceed  the  limit  of  their 
strength,  and  do  not  repair  their  loss  by  substantial  diet. 

Trainers  have  a  very  striking  expression  when  they 
wish  to  describe  a  horse  which  has  been  overtrained  ; 
they  say  that  the  horse  has  become  sta/e,  this  means 
that  the  excessive  work  it  has  undergone  has  consumed 
not  only  the  reserve  materials,  fats  and  other  substances 
not  directly  concerned  in  movement,  but  the  combustions 
have  attacked  the  horse  itself  considered  as  a  machine, 
and  its  muscular  tissues,  the  essential  motor  organs. 

Similarly  our  Hercules  at  the  fair  had  been  used  up 
by  excessive  muscular  work.  He  offered  a  type  of  a 
kind  of  overwork  very  different  from  that  we  have 
previously  described,  and  which  we  shall  call  organic 
exhaustion. 

I. 

The  form  of  overwork  which  we  call  organic  exhaus- 
tion is  a  condition  of  chronic  fatigue  in  which  the 
organism,  instead  of  absorbing  the  noxious  products  as 


OVERWORK.  I  5  5 

in  acute  fatigue  or  febrile  overwork,  is  despoiled  of  its 
useful  materials  and  of  the  tissues  most  necessary  for  life. 

This  condition  represents  usually  the  chronic  form  of 
fatigue,  but  it  can  come  on  very  quickly  when  there  is 
inanition  as  well  as  work.  There  results  a  defective 
balance  between  income  and  expenditure. 

If  a  man  performs  violent  exercise  and  his  nutriment 
is  proportioned  to  the  work,  the  system  can  repair  its 
losses  ;  and  the  work  having  a  tendency  to  distribute 
the  assimilated  materials  to  the  organs  which  participate 
in  the  action,  the  muscles  benefit  from  the  excessive 
nutriment,  and  the  machine  becomes  stronger.  But  if 
insufficient  food, is  taken,  or,  what  comes  to  the  same 
thing,  if  the  nutriment  introduced  into  the  stomach  is 
not  assimilated,  there  is  a  disproportion  between  the 
expenditure  of  heat  demanded  by  the  animal  machine, 
and  the  quantity  of  fuel  supplied  to  it  from  without. 
Now  movement  cannot  occur  without  heat,  and  heat 
cannot  be  produced  without  combustible  materials. 
Thus,  in  default  of  sufficient  food,  when  the  reserve 
materials  have  been  consumed  the  essential  organs  of 
life  have  to  serve  as  fuel.  A  man  who  eats  little  and 
works  much  may  be  compared  to  those  unfortunates 
who,  having  exhausted  all  their  fuel,  make  up  for  it  by 
burning  the  remains  of  their  furniture. 

It  is  not  always  a  profession  demanding  great  muscular 
force  which  leads  to  organic  exhaustion.  It  is  rather  an 
occupation  needing  a  great  many  hours  of  work.  The 
combustions  are  not  in  this  case  very  violent,  and  there 
is  time  for.the  elimination  of  the  waste-products  formed 
by  them  :  the  products  of  dissimilation  do  not  accumu- 
late in  the  system,  there  is  no  auto-intoxication,  but  many 
organic  substances  are  burned,  and  the  body  suffers. 

It  may  happen  that  a  man  becomes  exhausted  without 
experiencing  the  slightest  discomfort  from  fatigue,  and 
may  go  on  with  his  work,  steadily  losing  weight.  But 
when  the  system  is  deprived  of  some  of  its  essential 
materials,  he  falls  into  a  condition  of  "  diminished  resist- 
ance "  and  can  no  longer  defend  himself  against  the 


156  PHYSIOLOGY  OF  BODILY  EXERCISE. 

numerous  injurious  influences  which  may  act  upon  him 
from  without.  Exhaustion  is  the  most  important  predis- 
posing cause  of  all  diseases. 

It  is  convenient,  we  think,  to  make  a  capital  distinc- 
tion between  overwork  by  intoxication  and  overwork  by 
exhaustion.  In  the  first  case  there  is  an  infective  condi- 
tion, which  may  be  influenced  by  various  affections 
acting  from  without,  but  capable  in  itself  of  producing 
serious  illness,  and  even  death.  In  the  second  case  there 
is  a  condition  of  lowered  vital  resistance,  giving  to  the 
organism  greater  receptivity  for  diseases,  but  not  capable 
of  being  in  itself  an  illness. 

Take  an  exhausted  man,  put  him  in  better  hygienic 
conditions,  shield  him  from  all  germs  of  contagion,  he 
will  certainly  restore  in  time  the  tissues  he  has  lost. 
But  give  to  a  young  soldier  overworked  by  forced 
marches,  or  to  an  animal  which  has  been  hunted,  all  the 
best  conditions  of  repose,  food,  and  hygiene,  it  may 
happen  that  neither  will  escape  a  serious  illness,  and 
both  may  die. 

Organic  exhaustion  is  the  condition  in  which  a  man 
who  has  suffered  excessive  losses  finds  himself.  He  pre- 
sents an  analogy  with  all  morbid  conditions  character- 
ised by  a  considerable  diminution  of  the  organic  elements 
of  the  living  body.  Now  every  important  subtraction 
of  materials  which  form  an  integral  part  of  the  organism 
induces  a  general  condition  of  weakness  and  adynamia. 

It  is  well  known  that  exhaustion  results  from  too 
copious  sweating  caused  by  excessive  heat  or  by  any 
other  agent.  This  phenomenon  causes  sufficient  loss  of 
power  for  great  importance  to  be  attached  to  its  preven- 
tion in  exhausting  diseases,  phthisis  for  example. 

Diarrhoea  is  a  still  more  active  cause  of  exhaustion 
than  sweating,  and  it  will  carry  off  nursing  infants  in  a 
few  days  if  not  successfully  checked  at  the  onset.  The 
cholerine  of  adults,  by  the  rapid  and  abundant  loss  it 
occasions,  also  causes  profound  prostration  in  a  few 
hours.  Every  one  knows  the  profound  and  long-lasting 
exhaustion  caused  by  great  loss  of  blood. 


OVERWORK.  157 

All  fluxes,  all  losses  from  exag^î^erated  secretion,  cause 
a  diminution  of  the  strength  and  resisting  power  of  the 
patient,  and  render  him  more  liable  to  suffer  from  all 
causes  of  disease  to  which  he  may  be  exposed. 

Considering  these  facts  we  may  enunciate  this  axiom  : 

Whenever  a  man  is  in  normal  condition  a  consider- 
able loss  of  weight  is  a  proof  of  diminished  power  of 
resistance. 

The  organism  needs,  to  be  truly  strong  and  resisting, 
a  certain  mass  of  elements  ;  if  we  take  them  away  on  one 
side  we  must  restore  them  on  the  other,  and  what  we  re- 
move as  fat  from  a  man  or  a  horse  during  training,  we 
must  restore  in  the  form  of  muscle,  under  pain  of  throw- 
ing him  into  an  enfeebled  condition  which  lessens  his 
power  of  resistance. 

Why  does  the  organism  deprived  of  a  part  of  its 
elements  fall  into  a  condition  of  diminished  resistance  ? 
It  is  difficult  to  give  a  satisfactory  answer  to  this  ques- 
tion. We  may  say  that  the  elements  of  the  body  draw 
a  mutual  support  from  each  other,  and  that  in  the  struggle 
for  existence  each  contributes  its  part  for  the  common 
defence. 

The  essential  elements  of  the  blood  are  the  corpuscles. 
When  these  elements  are  diminished  in  number,  there  is 
a  condition  of  lessened  resistance  throughout  the  system. 
So  much  importance  is  attached  to  the  number  of  these 
corpuscles  when  we  wish  to  judge  of  the  gravity  of  the 
condition  of  the  patient,  that  apparatus  have  been  de- 
signed for  their  enumeration.  There, is  no  absurdity  in 
attributing  to  elements  forming  muscular  fibre,  or  to 
nerve-elements,  the  same  importance  as  to  the  blood 
corpuscles  in  estimating  the  power  of  resistance  of  the 
organism. 

However  incomplete  the  theory,  let  us  keep  fast  hold 
of  the  facts,  and  endeavour  to  throw  light  on  them.  Let 
us  above  all  endeavour  to  render  clear  the  practical  im- 
portance of  an  exact  knov/ledge  of  the  state  of  exhaus- 
tion, and  of  the  conditions  in  which  it  is  produced. 

12 


153  PHYSIOLOGY  OF  EODILY  EXERCISE. 


IL 

Exhaustion  due  to  muscular  work  generally  makes 
itself  felt  throughout  the  whole  system,  and  all  the  func- 
tions, all  the  organs,  seem  to  experience  its  influence. 
The  most  striking  symptom  of  this  phase  of  overwork  is 
a  condition  of  general  languor  of  the  functions  and  pros- 
tration of  the  powers,  a  condition  of  adynamia.  We  may 
notice  in  an  exhausted  man,  anaemia,  neuropathy,  diges- 
tive disturbances,  muscular  weakness,  etc. 

Sometimes  the  disturbances  seem  to  be  localised  in 
certain  organs,  or  in  certain  organic  systems,  according 
to  the  form  of  the  work  which  has  caused  exhaustion, 
and  according  to  the  accessory  conditions  under  which 
the  work  has  been  done  by  different  individuals. 

The  fact  which  most  strikes  one  who  observes  a  man 
exhausted  by  muscular  work,  is  the  diminution  in  size  of 
the  muscles  which  have  worked  to  excess.  The  man 
who  exhausts  himself  by  work  burns  up  his  muscular 
tissue,  and  we  thus  see  that  two  opposite  causes  lead  to 
the  same  effect.  Muscle  atrophies  from  inaction,  it 
atrophies  also  from  over-use  ;  whereas  moderate  work, 
accompanied  by  sufficient  nutriment,  increases  its  size 
and  strength. 

Exhaustion  may  show  its  effects  in  several  internal 
organs,  notably  the  heart.  The  heart,  being  a  muscle, 
should  hypertrophy  under  the  influence  of  muscular  work, 
for  all  increased  exercise  causes  increased  action  of  the 
heart-muscle.  Usually,  in  fact,  this  organ  does  become 
hypertrophied  in  the  true  sense  of  the  word,  that  is  to 
say  it  becomes  thicker,  heavier,  with  stronger  walls  and 
able  to  propel  the  blood  more  vigorously.  True  or 
concentric  hypertrophy  of  the  heart  has  been  observed  in 
many  athletes  and  gymnasts.  It  has  also  been  seen  in 
race-horses,  notably  in  the  celebrated  Eclipse,  whose 
heart  was  five  or  six  times  the  normal  weight.  But  in 
the  heart,  as  in  other  muscles,  excessive  exercise  induces 
wearing  and  degeneration  of  the  fibres,  lessens  the  resist- 
ing power  of  the  organism  and,  while  producing  dilata- 


OVERWORK.  159 

tîon  of  the  cavities  of  the  heart,  at  the  same  time  leads 
to  a  thinning  of  their  walls  and  to  diminished  strength  of 
their  fibres. 

This  condition  is  very  often  observed  in  persons  who 
have  abused  exercises  capable  of  inducing  overwork  of 
the  heart,  running  for  instance.  Professional  runners, 
some  of  whom  in  Africa  traverse  almost  incredible  dis- 
tances, are  in  the  end  usually  affected  with  passive 
dilatation  of  the  heart,  resulting  from  exhaustion  of  the 
organ.  They  have  generally  to  cease  active  work 
towards  the  age  of  forty  years,  and  they  then  suffer 
from  the  serious  disturbances  of  health  produced  by 
cardiac  affections. 

Sometimes  the  action  of  exhaustion  is  especially 
manifested  on  the  central  nervous  system,  and  the  ex- 
hausted man  becomes  neuropathic. 

Nervous  exhaustion  is  a  condition  which  has  been 
observed  and  studied  under  different  names  in  all 
periods,  and  of  w^hich  now,  more  than  ever  before,  we 
daily  see  examples.  It  is  the  termination  of  intellectual 
as  well  as  of  physical  overwork,  and  is  also  the  result  of 
excessive  enjoyment,  which  however  does  not  prevent 
its  being  also  an  accompaniment  of  violent  grief,  and  all 
forms  of  intense  mental  disturbance.  All  the  physical 
and  moral  causes  which  demand  an  undue  quantity  of 
work  from  the  nerve-centres  can  induce  a  state  of  fatigue 
analogous  to  that  observed  in  muscles  after  over-use. 

We  shall  show  later  how  certain  physical  exercises 
need  the  energetic  co-operation  of  the  nerve-centres  in 
the  work  of  the  muscles.  These  exercises,  if  practised 
to  excess,  can  then  lead  to  excessive  destruction  of 
certain  elements  of  the  nerve-fibres  and  cells.  It  is 
necessary  to  perform  an  intellectual  operation,  to  co- 
ordinate, weigh,  and  measure,  the  action  of  the  muscles 
in  all  exercises  of  precision.  Hence  the  neuropathic 
form  of  overwork  is  rather  the  result  of  such  exercises, 
than  of  those  grosser  forms  of  work  which  merely 
demand  a  mechanical  employment  of  physical  force. 
Hence  the  superiority  of  movements  which  need  no 
application,  no  apprenticeship,  when   we  have  to  deal 


l6o  PHYSIOLOGY  OF   BODILY  EXERCISE. 

with   patients   whose   nerve   centres   are   already  over- 
worked by  intellectual  labour. 

Whatever  exercise  is  practised,  however,  it  may  induce 
nervous  exhaustion,  for  the  nervous  substance  must 
come  into  play  to  produce  contraction  of  the  muscular 
elements,  and  when  the  brain  is  not  required  to  produce 
movements  —  in  automatic  actions  for  instance  —  it  is 
the  spinal  cord  which  comes  into  play,  and  it  is  this 
which  must  feel,  if  the  work  is  excessive,  the  effects  of 
overwork.  It  is  thus  that  the  coincidence  of  epilepsy 
with  forced  marches  has  been  pointed  out,  and  many 
observations  have  been  made  in  which  convulsive  dis- 
orders have  followed  the  traversal  of  long  distances  on 
foot  in  a  very  short  time. 

But  nervous  exhaustion  may  be  established  as  a  result 
of  overwork  in  a  more  indirect  manner.  Excessive 
work  may  produce  an  impoverishment  of  the  blood,  a 
condition  of  anaemia  which,  while  affecting  the  whole 
system,  may  more  especially  influence  the  nerve-centres 
in  predisposed  patients. 

Mental  physicians  have  long  pointed  out  that  ex- 
haustion and  anaemia  of  the  nerve  centres  is  a  frequent 
cause  of  certain  forms  of  melancholia.  We  have  our- 
selves been  able  to  observe  that  physical  overwork, 
impoverishing  the  constitution,  often  leads  to  certain 
remarkable  disturbances  of  the  cerebral  functions. 

During  a  country  medical  practice  of  eleven  years  we 
have  been  struck  by  a  considerable  number  of  cases  of 
mental  alienation  coming  in  series  at  certain  periods  oi 
the  year,  and  especially  struck  by  the  fact  that  all  these 
cases  presented  the  type  of  melancholia.  As  a  rule, 
these  patients  recovered  pretty  speedily,  and  their  mental 
disturbances  disappeared  in  two  or  three  months,  with- 
out the  necessity  of  confining  them  in  an  asylum.  After 
for  some  time  seeing  nothing  in  these  numerous  cases 
but  series,  simple  coincidences,  we  came  to  understand 
the  bond  connecting  them.  We  had  to  do  with  cases  of 
nervous  exhaustion  from  exaggerated  physical  fatigue. 

The  beginning  of  the  autumn  was  always  the  time 
when  we  observed  these  cases  of  transient  insanity,  and 


OVERWORK.  I6l 

it  is  just  at  this  time  that  the  great  labours  of  the 
harvest-season  come  to  an  end. 

For  those  who  know  the  Hfe  of  the  peasant  in  France, 
the  harvest  season  means  the  season  of  overwork.  In 
ordinary  times  country-people  make  no  great  expen- 
diture of  muscular  force.  They  are  always  on  their  feet, 
always  exposed  to  bad  weather,  always  engaged  in 
work  which  keeps  them  in  the  open  air  and  habituates 
them  to  exposure,  but  it  is  work  which  demands  neither 
great  speed  nor  great  muscular  exertion.  But  at  the 
end  of  June,  there  begins  a  period  of  three  months 
during  which  the  peasant  is  mowing  and  reaping, 
working  fast  for  fear  of  rain,  carrying  heavy  sheaves 
or  great  loads  of  hay.  The  countryman  is  then  leading 
an  athletic  life  and  sweating  profusely,  for  he  works 
under  a  burning  sun.  He  does  not  repair  his  strength 
by  sleep,  for  he  gets  up  very  early  in  the  morning  ;  his 
bed  is  uncomfortable,  he  is  eaten  up  by  parasites  of  all 
kinds,  further  he  is  ill-nourished  ;  instead  of  eating 
heartily  every  day  the  peasant  prefers  to  feed  like  a 
wolf,  and  he  reserves  himself  for  two  or  three  great  feasts 
in  which  he  gorges  himself  until  he  is  sick. 

Excessive  work,  excessive  perspiration,  insufficient 
food  and  sleep,  such  are  the  influences  to  which  the 
peasant  is  exposed  every  summer.  From  these  fatigues 
there  do  not  usually  result  the  febrile  disturbances 
which  we  have  described  as  occurring  in  persons  who 
abuse  work  without  preliminary  training,  for  the 
peasants,  who  work  always,  are  always  in  training.  The 
reaping  which  overworks  them  does  not  produce  in 
them  that  intoxication  by  waste-products  which  we  see 
in  persons  passing  from  inaction  to  forced  work.  The 
peasant,  wasted  by  daily  work  and  underfeeding,  has 
none  of  those  tissues  of  luxury  which  we  have  called 
reserve  materials.  Hence  in  him  fatigue  does  not  show 
itself  in  the  form  of  poisoning  of  the  system  and  of 
infective  fevers  of  a  typhoid  character,  but  by  à  con- 
dition of  exhaustion  of  varied  type,  in  which  nervous 
disorders  play  a  great  part. 

Owing  to  a  widely  spread  error,  it  is  generally  said 


1 62  PHYSIOLOGY  OF   BODILY   EXERCISE. 

that  work  in  the  fields  frees  the  peasant  from  the 
nervous  disorders  so  common  in  towns.  Public  opinion 
on  this  matter  is  founded  on  the  ideas  of  J.J.  Rousseau, 
and  other  intuitive  hygienists,  who  pretend  that,  given 
exercise,  open  air,  and  pure  morals,  no  illness  is 
possible.  It  is  merely  necessary  to  open  our  eyes  to 
assure  ourselves  that  these  preconceived  ideas  are  far 
from  being  in  accordance  with  the  facts. 

In  country-women  especially  we  are  able  to  study  the 
phenomena  of  exhaustion.  Like  the  men  they  work, 
perspire,  sleep  ill  and  feed  badly.  Further  they  have  to 
care  for  and  suckle  their  usually  very  numerous  children. 
The  life  of  a  young  mother  of  a  family  in  a  peasant  house- 
hold is  a  life  of  continual  exhaustion.  Hence  women 
in  towns  are  wrong  in  believing  themselves  to  have  a 
monopoly  of  nervous  disorders.  There  are  as  many 
neuropathies  in  the  country  as  in  the  town,  but  the 
neuropathies  of  the  country  have  not  such  noisy  mani- 
festations. This  moderation  in  the  symptoms  is  due  to 
the  simple  fact  that  these  patients  have  not  time 
to  complain,  and  the  persons  around  them  have  no 
time  to  sympathise  with  them.  They  do  not  suffer  less, 
but  they  hide  their  suffering  more,  for  fear  lest  their 
husbands  should  add  to  it  by  ill-treating  them.  But 
neuralgia,  gastralgia,  vertigo,  and  neuroses  of  all  kinds 
are  the  chief  illnesses  of  peasant-women  exhausted  by 
work.  As  regards  hysteria,  if  its  complete  manifesta- 
tions, in  the  form  of  seizures,  are  rarer  than  in  the  town, 
this  is  due  to  moral  causes  which  we  must  point  out  in 
passing.  For  women  of  the  world  "  to  be  nervous  "  is  a 
mark  of  distinction,  "to  have  crises"  is  always  a  means 
of  awakening  a  lively  interest  in  the  persons  around. 
In  the  country  a  "nervous  crisis"  is  synonymous  wiuh 
an  attack  of  epilepsy. 

The  salutary  fear  of  epilepsy  which  exists  in  the 
country  is  a  powerful  protection  against  the  convulsive 
movements  and  the  contortions  of  an  hysterical  fit,  in 
which  moral  causes  play  so  great  a  part. 


CHAPTER  X. 

THE   THEORY  OF   FATIGUE. 

Fatigue  is  a  Regulator  of  Work — Organic  Conditions  which 
hasten  the  onset  of  the  Sensation  of  Fatigue  ;  Weakness  of 
the  Organs  ;  Excess  of  Reserve  Materials — Order  and  con- 
nection of  Phenomena  of  Fatigue — Local  and  General  Fatigue; 
Imjiiediate  and  Consecutive  Fatigue — The  different  Processes 
of  Fatigue:  (i.)  Traumatic  Effects  of  Work  on  the  Motor 
Organs.  (2.)  Auto- Intoxication  by  the  Products  of  Dissimilation. 
(3.)  Orga7iic  Exhaustion  through  Aiitophagy.  (4.)  Dy?ia7nic 
Exhaustion  through  Expenditure  of  all  the  Force  at  the  Dis- 
posal of  the  Muscular  and  Nervous  Elements.  Insufficiency  of 
existing  Physiological  ideas  for  explaining  all  the  Phenomena 
of  Fatigue. 

We  have  reviewed  the  principal  physiological  pheno- 
mena which  accompany  work,  and  the  changes  in  the 
organism  which  result  from  muscular  activity.  We  can 
now  briefly  sum  up  and  expound  the  conclusions  to  be 
drawn. 

Taking  a  muscular  action  from  its  outset,  the  muscular 
contraction,  and  studying  it  to  its  termination,  which  is 
consecutive  fatigue,  .or  stiffness,  and  to  its  most  serious 
pathological  consequences,  overwork  and  organic  ex- 
haustion, we  can  give  a  complete  picture  of  the  pheno- 
mena of  fatigue,  and  we  can  formulate  a  rational 
theory. 

I. 

Fatigue  is  the  consequence  of  the  material  action 
exercised  by  work  on  the  organs  of  movement  and  on 
the  great  organic  systems  v/hich  associate  in  exercise. 
The  sensation   experienced  by  the  individual  after  ex- 


164  PHYSIOLOGY  OF   BODILY   EXERCISE. 

cessive  muscular  activity  is  a  true  regulator  of  work, 
which  becomes  the  more  sensitive  the  greater  the  danger 
which  the  exercise  is  causing  the  organism. 

In  a  much  enfeebled  man  the  sensation  of  fatigue  is 
very  painful  :  this  is  because  in  a  very  feeble  body  the 
organs,  having  less  resistance,  undergo  more  easily  the 
damages  due  to  fatigue.  In  a  man  of  inactive  life, 
whose  body  is  overcharged  with  reserve  materials,  very 
intense  fatigue  is  produced  by  very  little  work.  This  is 
because  violent  exercise  would,  owing  to  the  excessive 
quantity  of  reserve  materials,  very  quickly  induce  stiff- 
ness and  overwork. 

If  we  examine  together  the  phenomena  of  work  and 
the  phenomena  of  fatigue,  it  is  easy  to  see  that  the  one 
set  is  derived  from  the  other,  and  it  is  easy  to  grasp  the 
relations  of  cause  and  effect  by  which  they  are  united. 

When  a  muscle  contracts  forcibly,  there  occur  in  all 
the  sensitive  parts  of  the  region  performing  the  work 
shocks  and  frictions  which  cause  pain.  There  occurs 
further  in  the  muscle,  by  the  very  fact  of  work,  a  process 
of  dissimilation  leading  to  the  formation  of  organic 
poisonous  substances,  and  the  presence  of  these  products 
of  combustion  is  the  cause  of  the  sensation  of  local 
powerlessness  experienced  in  a  muscle  which  has  been 
at  work. 

But  the  whole  organism  associates  in  the  work  of  a 
single  muscle.  By  the  very  fact  of  muscular  contraction 
the  blood  undergoes  an  acceleration  which  necessitates 
increased  activity  of  the  heart.  The  lungs  receive  more 
blood  than  usual  and  become  congested,  the  respiratory 
movements  are  increased  in  frequency.  Then  a  new 
cause  of  discomfort  comes  into  play,  the  saturation  of 
the  blood  by  carbonic  acid,  resulting  from  the  combus- 
tion of  work,  A  general  suffering  in  the  system  results 
from  this  tr?nsient  intoxication,  against  which  the  lungs 
strive  by  their  efforts  to  expel  the  noxious  gas  :  breath- 
lessness  comes  0:1. 

To  breathlessness  are  added  the  painful  sensations 
due  to  the  heating  of  the  blood,  and  to  the  influence 
which  this  overheated  blood  has  on  the  nerve-centres. 


THE   THEORY   OF   FATIGUE.  1 65 

and  thus  is  completed  the  picture  of  General  Fatigue 
following  exercise. 

But  as  soon  as  the  work  is  over,  the  functional  dis- 
turbances of  the  heart  and  lungs  diminish,  through  the 
slowing  of  the  blood  current.  At  the  same  time  the 
production  of  carbonic  acid  diminishes,  and  the  excess 
which  had  been  formed  is  rapidly  eliminated.  The 
temperature  of  the  blood  falls  through  radiation,  and 
through  evaporation  of  the  sweat  with  which  the  body 
is  bathed. 

All  disorder  should  then  cease,  but  if  the  exercise  has 
been  carried  too  far,  the  organism,  notwithstanding  the 
muscular  repose,  finds  itself  under  the  influence  of  a 
persistent  suffering  which  is  Consecutive  Fatigue.  The 
limbs  which  have  been  at  work  still  suffer  from  some 
pain  which  is  not  entirely  dissipated  by  repose,  for  the 
muscles  have  been  subjected  to  actual  mechanical  lesions 
during  the  work  :  shocks,  little  lacerations  of  fibrillae, 
frictions  of  surrounding  sheaths  and  synovial  mem- 
branes, contusions  of  joints. 

But  there  are  other  troubles  which  are  not  to  be  ex- 
plained by  any  mechanical  cause  :  these  are  the  fever, 
the  general  discomfort,  the  feeling  of  weakness  and  pros- 
tration, symptoms  indicating  that  the  organism  is  under 
the  influence  of  a  toxic  agent.  These  disorders  are  due 
to  the  passage  into  the  blood  of  the  products  of  dissimi- 
lation with  which  the  muscles  are  loaded,  and  which  the 
blood  gradually  removes  from  the  muscular  fibres  in 
order  to  carry  them  to  the  kidneys  whose  office  it  is  to 
remove  them  from  the  system.  The  cleansing  of  the 
muscular  machine  by  the  blood  lasts  the  4onger  the 
greater  the  amount  of  dross  left  by  the  exercise. 

During  the  time  which  elapses  between  the  formation 
of  these  waste  products  and  their  expulsion  by  the  urine, 
the  system  is  in  a  condition  of  real  poisoning,  whence 
arise  the  fever  of  stiffness  and  the  sensation  of  general 
discomfort.  The  nitrogenous  waste-products  to  which 
febrile  stiffness  is  due,  are  slowly  removed  from 
the  muscles  and  slowly  eliminated  by  the  kidneys. 
During    the     time     preceding    their    elimination     the 


I66  PHYSIOLOGY  OF   BODILY   EXERCISE, 

organism  is  under  their  influence  and  is  struggling 
against  them. 

Thus  is  explained  the  slow  onset  of  consecutive 
fatigue,  and  its  persistence  after  the  work  is  over. 

Finally,  if  the  waste-products  are  too  abundant,  or 
the  resisting  power  of  the  organism  insufficient,  these 
noxious  substances  give  rise,  by  a  process  of  which  we 
are  ignorant,  to  other  similar  substances,  which  renew 
themselves  in  the  blood  during  many  days,  and  give 
rise  to  the  severe  fevers  of  overwork. 

We  are  thus  led  to  say  that  the  starting  point  of  all 
the  general  phenomena  of  fatigue  is  a  poisoning  of  the 
organism  by  its  own  products  of  dissimilation.  All  the 
phases  of  general  fatigue,  from  the  simple  discomfort 
which  causes  momentary  muscular  powerlessness,  to 
extreme  breathlessness  to  which  animals  succumb,  and 
to  the  fever  of  overwork  which  simulates  typhus,  are 
due  to  these  more  or  less  active  poisonous  substances, 
retained  a  longer  or  a  shorter  time  in  the  blood. 

But  all  the  disturbances  of  nutrition  which  follow  work 
are  not  to  be  explained  by  an  auto-intoxication  of  the 
body.  In  certain  forms  of  overwork  we  see  the  pro- 
cesses of  nutrition  carried  on  by  feeding  on  the  tissues 
most  essential  to  life.  The  reserve  materials  being  ex- 
hausted, the  tissues  forming  the  woof  of  the  organs  are 
in  turn  attacked,  and  the  body,  instead  of  assimilating 
its  own  noxious  materials,  as  in  the  other  forms  of  over- 
work, robs  itself  on  the  contrary  of  the  organic  elements 
indispensable  to  the  equilibrium  of  health.  There  is  no 
longer,  in  this  case,  auto-intoxication,  but  aiitopJiagy  and 
exhaustion. 

II. 

Among  the  phenomena  of  fatigue  there  is  a  whole 
series  of  which  the  methodical  classification  seems  at 
present  impossible,  because  too  little  is  known  about 
them.  They  cannot  be  classed  with  the  mechanical 
phenomena,  such  as  the  little  lesions  from  which  the 
muscle  suffers,  nor  with  the  nutritive  disturbances  such 


THE   THEORY   OF   FATIGUE.  1 67 

as  the  intoxications  due  to  waste  products,  and  the 
exhaustion  due  to  diminution  of  the  mass  of  the  organic 
tissues.  We  shall  call  them  the  dynamic  phenomena  of 
fatigue,  because  they  seem  to  manifest  themselves  simply 
by  a  loss  of  force,  without  any  lesion,  any  chemical 
change,  any  loss  of  substance,  being  discoverable  in  the 
organ.  When  we  hold  the  arm  outstretched,  at  the  end 
of  five  minutes  we  are  forced  to  lower  it  by  fatiguCé 

What  has  happened  in  the  muscles  during  the  short 
time  contraction  has  lasted  ?  The  fatigue  is  not  due  to 
the  formation  of  waste-products  ;  five  minutes  of  con- 
traction would  not  suffice  profoundly  to  alter  the  nutri- 
tion of  the  muscles  ;  it  is  not  due  to  material  frictions  of 
the  fibres  ;  it  would  last  longer.  We  can  only  suppose, 
in  the  case  we  are  considering,  that  there  is  a  dynamic 
effect,  a  loss  of  the  energy  contained  in  the  muscle,  with- 
out any  anatomical  change  being  appreciable  in  its 
tissue. 

This  dynamic  fatigue  of  muscle  is  quite  similar  to  that 
which  may  be  observed  in  nerve-elements  after  over-use. 
If  a  nerve  be  stimulated  very  frequently,  it  ends  by 
losing  for  a  time  the  power  of  transmitting  stimuli  : 
similarly  the  nerve-centres  lose  their  auto-motor  power 
when  they  have  been  in  action  too  long. 

We  call  an  organ  which  has  thus  momentarily  lost 
its  specific  energy  exhausted  ;  but  we  must  not  confuse 
this  dynamic  exhaustion  with  the  organic  exhaustion 
which  we  have  described,  and  which  is  characterised  by 
the  diminution  of  certain  anatomical  elements.  hi 
exhausted  nervous  tissue,  we  do  not  see  any  diminution 
in  the  mass  of  material  molecules,  but  simply  a  lessened 
manifestation  of  the  energy  peculiar  to  these  molecules. 

Can  we  discover  in  fatigued  nerves  nutritive  disturb- 
ances at  present  ill-understood?  Everything  leads  to 
this  belief,  for  we  know  that  nervous  tissue  becomes 
heated'  and  congested  when  in  action.  Its  work  is 
subject  to  the  same  physiological  conditions  as  that  of 
muscle,  and  its  fatigue  should  be  subject  to  the  same 
laws.  But  in  muscle  we  have  been  able  to  establish  that 
there  is  an   exhaustion  of  muscular  contractility,  which 


l68  PHYSIOLOGY   OF   BODILY   EXERCISE. 

seems  due,  in  certain  cases,  to  a  similar  expenditure  of 
the  energy  of  the  fibres,  independently  of  any  intoxica- 
tion by  products  of  dissimilation,  and  of  any  material 
loss  in  the  organ.  We  cannot  then  refuse  to  admit, 
among  the  phenomena  of  fatigue,  a  series  of  phenomena 
due  to  a  simple  loss  of  vital  energy  in  consequence  of 
the  very  activity  of  the  element  which  has  been  at  work. 
We  must  make  a  provisional  category  of  these  facts 
under  the  title  of  dynamic  fatigue^  and  admit  that  this 
form  of  fatigue  is  due  in  the  nerves  and  nerve-centres,  to 
a  too  great  expenditure  of  the  force  which  we  will  call, 
for  want  of  a  bettei  name,  nervous  energy. 

Nervous  energy,  like  heat  and  electricity,  results  from 
the  liberation  of  a  force  which  existed  as  latent  energy 
in  the  molecules  of  the  nervous  substance,  from  which 
certain  circumstances  have  caused  its  discharge.  A  bar 
of  red  hot  iron  plunged  into  water  cools  by  loss  of  heat 
which  the  cold  liquid  abstracts  from  it.  A  nerve  which 
is  stimulated  in  order  to  cause  a  muscular  contraction 
seems  to  be  deprived  by  its  work  of  transmission  of  a 
certain  quantity  of  energy,  and  just  as  the  red  hot  iron 
had  only  a  definite  quantity  of  heat  to  give  up,  so  the 
nerve  when  at  rest  had  only  a  limited  quantity  of 
nervous  energy  at  its  disposal,  which  has  been  expended 
in  the  work. 

The  analogy  up  to  this  point  seems  satisfactory;  it 
ceases  to  be  so  when  we  consider  that  the  heat  lost  by 
the  cooled  iron  is  not  spontaneously  reproduced,  while 
the  nerve,  left  to  itself,  recovers  its  energy  after  a  little 
time.  The  provision  of  force  which  has  been  exhausted 
is  renewed  without  any  other  condition  being  necessary 
than  a  temporary  cessation  of  expenditure, 

Let  us  suppose  there  is  a  large  reservoir  in  which  the 
water  gradually  accumulates  from  a  very  feeble  source 
of  supply.  Open  the  reservoir  and  use  the  water  con- 
tained in  it  to  move  a  water-wheel  :  after  a  time  the 
supply  of  water  is  exhausted  and  the  wheel  no  longer 
turns.  But  the  conduit  does  not  cease  to  feed  the 
reservoir,  and  if  the  outflow  is  stopped  the  mass  which 
gradually  accumulates   will   soon    become  sufficient   to 


THE  THEORY  OF  FATIGUE.  169 

move  the  wheel  again.  Such  is,  in  default  of  a  satis- 
factory explanation,  the  simile  we  propose,  that  we  may- 
make  the  succession  of  the  phenomena  understood. 

We  have  been  obliged  to  give  the  reader  as  complete 
and  clear  a  theory  of  fatigue  as  was  possible  ;  the  gaps 
and  imperfections  in  this  chapter  will  be  excused,  in 
consideration  of  its  novelty.  No  author  has  hitherto 
arranged  after  a  methodical  plan  all  the  phenomena 
which  may  be  a  consequence  of  work,  or  has  en- 
deavoured to  determine  their  laws. 

The  phenomena  of  fatigue  are  local  or  general,  im- 
viediate  or  conseaitiTe.  If  w^e  endeavour  to  sum  up  the 
physiological  laws  according  to  which  these  phenomena 
are  evolved,  w^e  shall  see  that  they  relate  to  four  orders 
of  causes  : 

1.  Material  lesiuus  of  the  motor  organs 

2.  Auto-intoxication  by  the  w^aste-products  of  work* 

3.  Exaggerated  use  of  the  living  tissues. 

4.  Dynamic  exhaustion  of  the  motor  elements. 


CHAPTER  XI. 

REPOSE. 

Repair  of  the  Animal  Machine — Cleansing  of  the  Organs  ;  Elimi- 
nation of  the  Waste  Products  of  Combustion — Diminution  of 
Combustions  during  Repose — Fall  of  Temperature  and  De- 
pression of  Vital  P^unctions  during  Sleep — The  Duration  of 
Repose  must  vary  according  to  the  Form  of  Fatigue — Short 
Period  of  Repose  necessary  to  dissipate  Bieathlessness — The 
Runners  of  Tunis — Difference  in  the  Rapidity  of  Elimination  of 
the  various  Products  of  Dissimilation — Dynamic  Effects  of 
Repose  ;  they  are  still  unexplained — Iniluence  of  Periods  of 
Repose  in  relation  to  the  Conservation  of  Energy — The  Enghsh 
Boxers. 

I. 

In  a  steam  engine,  barring  accidents,  the  work  con- 
tinues as  long  as  the  fire  is  kept  up. 

In  the  human  body,  in  spite  of  the  richest  diet,  mus- 
cular movement  becomes  impossible  after  a  certain 
period  of  exercise,  and  the  work  is  necessarily  stopped  : 
the  organism  has  need  of  repose.  The  human  machine 
can  only  work  intermittently.  But  this  apparent  imper- 
fection is  in  reality  the  result  of  a  great  superiority  to 
the  steam  engine.  Repose  is  wanted  because  of  the 
power  of  repair  possessed  by  the  living  organism. 

The  machine  at  work  is  slowly  but  fatally  used  ap  : 
the  more  work  it  does,  the  less  it  becomes  fitted  for 
work.  We  can  calculate  in  advance  the  amount  of 
work  in  kilogrammetres  which  an  apparatus  or  instru- 
ment will  be  able  to  perform  before  it  is  used  up.  A 
cannon  is  useless  after  a  certain  number  of  shots  has 
been  fired.      The  more  a  machine  performs,  the  more  it 


REPOSE.  171 

deteriorates,  and  loses  its  fitness  for  performance.  Con- 
trariwise, the  more  the  Jiving  body  works,  the  more 
resistant,  and  the  fitter  for  work  it  becomes.  It  is  a 
law  of  vital  movement  that  function  strengthens  the 
organ,  whereas  the  working  of  a  machine  wears  out  its 
wheels. 

The  organs  of  the  human  body  repair  the  losses  which 
they  have  suffered  during  work,  and  make  in  compensa- 
tion new  acquisitions  ;  now  it  is  a  law  of  life  that  the 
losses  of  work  are  not  repaired  during  the  work,  but 
only  after  it  is  over.  A  period  of  repose  is  then 
necessary  that  the  organs  may  repair  the  losses  they 
have  suffered  during  the  period  of  activity. 

What  is  the  nature  of  the  actions  which  join  in  repair 
of  the  organs  after  a  period  of  activity  ?  These  actions 
are  numerous  and  complicated  ;  some  of  them  are  known 
to  us,  but  we  are  still  ignorant  of  many. 

Repair  of  the  organs  is,  strictly  speaking,  a  complete 
renovation  of  the  organs.  A  muscle  which  works  makes 
waste,  that  is  to  say  is  the  poorer  for  certain  portions  of 
its  tissue  which  are  detached  from  the  organ  and  rejected. 
In  their  place  the  blood,  drawn  to  the  muscle  in  abun- 
dance by  the  very  act  of  contraction,  carries  to  it  new 
materials  which  are  installed  in  place  of  those  which 
have  been  eliminated.  Every  moment  a  fresh  particle 
is  being  detached  as  waste,  and  its  place  being  taken  by 
a  molecule  of  new  formation.  In  this  manner  the 
muscle  is  in  the  end  entirely  renovated,  and  it  is  thus 
that  the  prpcess  of  nutrition  makes  the  new  instruments 
of  work. 

Thus  the  body  is  a  machine  the  wheels  of  which  are 
constantly  renewing  themselves  and  undergoing  continual 
repair.  It  is  owing  to  this  repair  that  the  body  is  not 
worn  out  by  work. 

The  blood  current  passing  through  a  muscle  exercises 
on  it  a  true  process  of  cleansing  by  disembarrassing  it 
of  the  waste  products  of  combustion  resulting  from 
work.  This  cleansing  takes  rather  a  long  time,  for 
according  to  our  observations,  twelve,  and  even  twenty- 
four  hours  are  sometimes  necessary  for  the  elimination 


172  PHYSIOLOGY   OF   BODILY   EXERCISE. 

of  the  waste  products  by  the  urine.  During  this  time 
successive  waves  of  blood  carry  off  the  deteriorated 
molecules  which  form  the  waste  products,  and  at  the 
same  time  carry  to  the  muscles  from  which  these  waste 
products  are  being  given  off,  nitrogenous  materials  which 
are  necessary  to  replace  them. 

It  is  easy  to  understand  that  this  operation  cannot  be 
properly  accomplished  until  the  work  is  over,  for  the 
continual  formation  of  new  waste  products  annihilates 
the  result  of  the  cleansing  performed  by  the  blood 
current.  The  materials  for  the  re-formation  of  the  tissues 
cannot  be  assimilated  by  the  latter  while  they  are  still 
loaded  with  waste  products  which,  pending  their  expul- 
sion, act  as  foreign  bodies,  and  the  muscle  is  not  repaired. 

The  result  of  an  insufficient  period  of  repose  will 
then  be,  on  the  one  hand,  the  accumulation  of  the 
materials  damaged  by  combustions,  and  on  the  other 
defective  repair,  insufficient  nutrition  of  the  organs  of 
work. 

It  is  in  this  way  that  auto-infection  by  the  waste  pro- 
ducts of  work,  a  consequence  of  overwork,  is  produced 
in  individuals  who  have  to  work  for  too  long  a  time, 
and  whose  periods  of  rest  are  too  short  and  too  infre- 
quent. Further,  insufficient  repose  leads  to  exhaustion 
and  to  diminished  mass  of  the  tissues  burned  up  by  the 
work.  However  abundant  the  nutriment,  an  exercise 
too  long  continued  or  too  often  repeated  will  lead  to 
loss  of  flesh,  because  there  is  not  time  for  the  processes 
of  nutrition  to  transform  into  tissue  the  niaterials  elabo- 
rated by  digestion. 

It  is  necessary  then,  in  the  hygiene  of  exercise,  care- 
fully to  balance  the  periods  of  work  and  the  periods  of 
repose.  The  more  or  less  frequent  repetitions  of  periods 
of  repose  is  as  important  to  define  as  the  quantity  of 
work  done. 

All  exercises  do  not  need  the  same  periods  of  repose  ; 
the  time  for  which  exercises  can  be  continued  without 
inconvenience  is  variable. 

Exercises  which  produce  breathlessness  render  neces- 
sary very   frequent  rests,  but  these  may  be  very  short 


REPOSE.  173 

These  exercises  produce  much  carbonic  acid  in  a  very 
short  time.  This  product  of  combustion  can  very  quickly 
cause  serious  accidents  :  whence  the  necessity  for  its 
prompt  ehmination.  On  the  other  hand  it  is  very  vola- 
tile and  very  easily  displaced  ;  hence  it  is  very  quickly 
removed  from  the  system  in  the  breath.  In  certain  dis- 
tricts of  Tunis  there  are  still  commissionary  runners  or 
carriers  of  despatches,  called  rekas,  who  have  an  unpa- 
ralleled power  of  resisting  fatigue  and  breathlessness. 

When  a  reka  finds  that  his  respiration  is  becoming 
embarrassed  he  stops,  counts  up  to  sixty,  and  starts 
afresh.     In  this  rest  he  regains  his  breath. 

Exercise  of  endurance  causes  fatigue  less  quickly  than 
exercise  of  speed,  but  it  necessitates  longer  repose.  A 
walker  who  is  not  accustomed  to  long  distances  can,  if 
an  energetic  man,  walk  for  five  or  six  hours  without  stop- 
ping ;  but  if  fatigue  comes  on  slowly,  it  is  also  slow  to 
disappear,  and  it  would  not  be  merely  one  or  two 
minutes  before  he  could  start  again,  but  one,  or  even  two 
days.  This  is  because  the  waste  products  of  fatigue  are 
not  in  this  case,  gaseous  substances,  like  carbonic  acid 
and  aqueous  vapour,  and  cannot  be  very  rapidly  elimi- 
nated from  the  system.  These  waste  products,  as  we 
have  explained,  are  nitrogenous  substances,  solids,  spar- 
ingly soluble,  and  needing  a  long  time  (six  to  eighteen 
hours)  for  their  elimination  from  the  body  by  the  urine. 
Hence  the  lengthy  period  of  repose  which  is  necessary. 
If  the  exercise  is  begun  again  too  soon,  if  the  period  of 
repose  is  too  short,  new  waste  products  are  formed  before 
those  which  had  collected  have  been  eliminated  from  the 
body,  and  their  accumulation  will  become  excessive.  In 
this  w^ay  the  various  degrees  of  intoxication  due  to  over- 
work are  produced. 

Rest  is  then  the  essential  condition  for  the  elimination 
of  the  waste  products  of  work  ;  for  during  rest  the 
formation  of  these  waste  products  is  lessened.  It  is  also 
the  essential  condition  for  the  repair  of  the  organs,  be- 
cause the  process  of  assimilation  in  virtue  of  which  repair 
takes  place  is  hindered  by  the  process  of  dissimilation 
which  goes  on  so  actively  during  work. 

13 


174  PHYSIOLOGY  OF  BODILY  EXERCISE. 


II. 

But  the  elimination  of  the  products  of  dissimilation 
and  the  repair  of  the  tissues  do  not  explain  all  the  ways 
in  which  repose  gives  to  fatigued  muscles  a  new  power 
of  contraction. 

When  the  arm  is  horizontally  outstretched,  and,  after 
five  minutes,  fatigue  compels  us  to  drop  it,  it  is  enough 
to  leave  it  inactive  for  a  minute  to  become  able  to  hold 
it  out  again.  What  has  happened  in  the  muscle  during 
this  period  of  repose  ? 

It  has  been  too  short  to  allow  the  blood-current  to 
wash  out  the  muscle,  and  to  carry  away  waste-products 
which  are  loading  its  fibres.  Further,  a  minute  would  not 
suffice  for  the  material  repair  by  the  substances  brought 
in  the  blood,  of  the  losses  undergone.  We  must  suppose 
a  dynamic  effect,  although  we  are  unable  exactly  to  say 
in  what  it  consists. 

The  muscle,  by  the  very  fact  of  ceasing  to  work,  makes 
a  new  provision  of  this  force  inherent  in  its  fibres,  con- 
tractility, which  the  long  effort  had  exhausted. 

This  explanation  is  more  like  a  confession  of  ignorance 
than  a  theory  ;  but,  however  insufficient  it  be,  it  conforms 
to  the  facts,  in  the  sense  in  which  it  implies  the  existence 
of  a  force  peculiar  to  the  muscle,  and  independent  of 
that  brought  to  it  from  outside.  If  we  cut  off  all  com- 
munication of  the  muscle  with  its  nutrient  vessels  bring- 
ing blood  ;  if  we  divide  all  the  nerve  filaments  which 
connect  it  with  the  motor  centres  of  the  spinal  cord  and 
the  brain,  the  muscle,  thus  reduced  to  the  unassisted 
energy  of  its  own  elements,  will  be  able  to  pass  through 
the  alternate  stages  of  exhaustion  by  work,  and  of  return 
to  power  of  contraction  under  the  influence  of  repose, 
just  as  if  it  were  still  in  association  with  the  organs  of 
circulation  and  innervation.  If  we  stimulate  it  electri- 
cally without  stopping,  it  will  become  fatigued,  and  will 
cease  to  respond  to  the  current  ;  if  we  then  leave  it  for 
a  certain  time  at  rest,  its  power  of  contraction  will 
gradually  be  restored,  as  if  its  elements  were  capable  of 


REPOSE.  175 

constantly  elaborating  a  certain  quantity  of  contractile 
force  to  replace  that  which  has  been  exhausted  by  too 
prolonged  contraction. 

There  is  a  last  category  of  phenomena  for  the  expla- 
nation of  which  another  influence  must  be  invoked,  if  we 
wish  completely  to  account  for  the  effect  of  repose.  The 
cessation  of  a  muscular  effort  seems  sometimes  merely 
to  have  as  its  object  the  stoppage  of  the  pain  which 
contraction  is  causing  in  the  muscle. 

A  muscle  is  traversed  by  numerous  sensory  nerve- 
filaments,  and  these  filaments  are  necessarily  rubbed 
when  a  muscle  contracts.  Everyone  knows  a  pheno- 
menon which  shows  how  painful  muscular  contraction 
may  become  when  it  is  extreme  in  degree  ;  cramp  is 
merely  involuntary  and  exaggerated  muscular  contrac- 
tion. It  shows  how  painful  are  the  effects  which  may  be 
produced  by  muscular  contraction.  The  pain  accom- 
panying the  persistent  rubbing  and  shaking  of  the 
sensory  nerves  by  the  muscle  is  often  the  true  cause  of 
the  sensation  which  urges  and  compels  us  to  relax  the 
muscle,  and  give  up  a  fatiguing  position.  A  thing  which 
seems  to  confirm  this  hypothesis  is  the  power  possessed 
by  hypnotised  persons  of  supporting  during  a  very 
prolonged  time  extremely  fatiguing  attitudes,  such  as 
that  with  the  arm  outstretched,  without  any  sensation 
of  fatigue.  We  may  believe  that,  in  these  persons,  the 
absence  of  fatigue  is  due  to  anaesthesia  of  the  nerve 
filaments  and  the  abolition  of  painful  sensations.  This 
anaesthesia  is  manifested,  as  is  well  known,  by  all  nerves 
during  the  hypnotic  state,  for  the  skin  may  be  pinched 
or  deeply  pricked  with  pins  without  causing  any  pain. 

Thus  to  sum  up,  the  effects  of  muscular  repose  are 
these  : — 

1.  The  cessation  of  certain  painful  sensations  when 
the  contractions  which  cause  painful  frictions  of  nerve- 
fibres  and  shocks  of  muscle-fibres  cease. 

2.  Time  is  given  for  the  elimination  of  the  waste 
products  of  combustion. 


1/6  PHYSIOLOGY  OF   BODILY   EXERCISE. 

3.  The  plastic  elements  of  the  blood  are  enabled  to 
repair  the  materials  removed  from  the  organs  during  the 
combustions  of  work. 

4.  Finally,  time  is  given  to  the  muscular  and  nervous 
elements  for  making  a  new  provision  of  energy  by  a 
physiological  mechanism  which  is  still  unknown. 

Repose  is  the  condition  which  is  diametrically  op- 
posed to  work,  and  the  phenomena  observed  in  these 
two  so  different  states  are  absolutely  inverse.  Muscular 
work  causes  exaggeration  of  vital  phenomena,  and  gives 
to  all  the  functions  a  greater  intensity  :  it  quickens  the 
pulse  and  respiration  and  raises  the  temperature  of  the 
body.  Rest  slows  the  pulse  and  respiration  and  lowers 
the  temperature. 

Like  work,  repose  has  its  degrees,  and  these  degrees 
are  very  relative.  In  a  practised  runner,  to  walk  for  a 
time  is  to  rest  ;  in  the  sick  man,  used  to  lie  on  his  back, 
to  sit  upright  is  work. 

Sleep  is  complete  repose,  because  in  this  condition  all 
the  muscles  of  animal  life  are  relaxed,  and  those  of 
organic  life  work  with  less  energy.  The  respiration  and 
pulse  are  less  frequent,  the  temperature  lower  than  in  the 
waking  state.  Further,  an  organ  which  works  without 
ceasing  when  we  are  awake,  the  brain,  rests  during  sleep, 
and  the  circulation  in  it  is  less  active,  as  has  actually  been 
observed  in  men  with  holes  in  the  skull. 

The  fall  of  temperature  during  sleep  is  a  proof  of 
diminished  combustion,  and  of  minimal  formation  of 
waste  products.  Further,  it  has  been  observed  that  only 
half  as  much  carbonic  acid  is  eliminated  in  the  sleeping 
as  in  the  waking  state. 

The  fatigue  produced  by  continuous  work  is  intense 
in  proportion  to  the  expenditure  of  force.  A  violent 
effort  cannot  be  long  sustained  ;  but  if  the  most  violent 
exercise  is  interrupted  by  periods  of  rest  which,  though 
very  short,  are  sufficiently  frequent,  the  exercise  may  be 
carried  on  for  a  very  long  time. 


REPOSE.  177 

In  prize-fights,  the  fight  is  stopped  every  two  or 
three  minutes,  and  two  minutes'  rest  is  taken.  This 
interruption  of  the  fight  at  short  intervals  would  seem  at 
first  to  lessen  its  brutality  ;  but  it  is  really  a  way  of 
rendering  its  results  more  murderous.  Formerly,  when 
the  rounds  were  longer,  lasting  ten  minutes,  the  boxers 
quickly  became  fatigued.  Their  blows  became  less 
certain,  and  produced  less  serious  injuries.  Weariness, 
quite  as  much  as  wounds,  made  it  impossible  to  con- 
tinue the  fight.  Now-a-days,  with  short  rounds  and 
frequent  rests,  the  adversaries  husband  their  strength, 
and  their  blows  are  as  hard  at  the  end  as  they  were  at 
first.  The  beaten  man  has  to  yield,  not  because  he  is 
wearied,  but  because  he  is  seriously  injured.  In  spite 
of  their  strength  and  their  wonderful  staying  powers, 
the  combatants  could  not,  without  these  periods  of  rest, 
endure  the  prolonged  fatigues  of  these  fights,  which  often 
last  several  hours. 


PART    III. 
HABITUATION  TO  WORK. 

POWER  OF  RESISTING  FATIGUE — MODIFICATION  OF 
ORGANS  BY  WORK — MODIFICATION  OF  FUNC- 
TIONS  OF   THE   TISSUES    BY    WORK — TRAINING. 


CHAPTER   I. 

POWER    OF    RESISTING    FATIGUE. 

Variability  in  the  Power  of  Resisting  Fatigue — Effects  of  In- 
action— Effects  of  Habitual  Activity — Diffeient  Mode  of  Life 
causes  Different  Conformation  ;  Frugivorous  Animals  and 
Hunting  Animals  ;  the  Flesh  of  the  Haie  ana  the  Flesh  of  the 
Wolf — The  Labourer  and  the  Scholar — How  we  must  explain 
"  Habituation  ''  to  Work. 

Men  who  have  for  a  long  time  abstained  from  bodily 
exercise,  and  whose  system  most  keenly  suffers  from 
the  want  of  it,  are  those  by  whom  fatigue  is  most  to 
be  dreaded,  and  those  who  have  most  risk  of  suffering 
from  overwork.  Those  who,  on  the  contrary,  daily  per- 
form muscular  work  acquire  the  power  of  braving  fatigue 
and  successfully  striving  against  its  most  serious  mani- 
festations. 

But  this  immunity  which  is  gained  by  work  is  very 
quickly  lost  by  inaction  ;  it  can  only  be  preserved  by 
the  habitual  practice  of  muscular  exercise. 

We  may  say  that  too  prolonged  repose  is  the  condi- 
tion which  most  effectively  predisposes  the  organism  to 
fatigue.  Stiffness  is  unknown  to  men  who  lead  a  life 
of  continual  muscular  activity,  and  the  consequences  of 
overwork  affect  them  with  difficulty.  Fatigue  in  all  its 
forms  and  all  its  degrees  especially  makes  its  effects  felt 
on  those  who  take  too  much  rest.  We  see  women 
who  never  walk  a  step  in  the  street  ;  their  carriage 
renders  it  unnecessary  ;  they  do  not  even  make  any 
movements  in  dressing  themselves  ;  they  have  a  maid 
to  save  them  the  trouble.  These  persons  suffer  from 
stiffness  if  they  walk  the  length  of  the  street.  If  one 
day    by   chance,  on   the   advice  of  their  medical  man, 


l82  PHYSIOLOGY  OF  BODILY  EXERCISE. 

they  decide  upon  an  hour's  walk,  they  are  in  bed  with 
a  fever  the  next  morning.  The  doctor  is  sent  for  with 
all  speed,  and  it  is  explained  to  him  how  barbarous  he 
has  been  to  compel  his  patient  to  use  her  legs.  On 
the  other  hand,  a  postman  in  the  country  walks  his  20 
to  25  miles  a  day,  goes  to  bed  without  feeling  any  the 
worse,  and  wakes  up  each  morning  the  more  fit  for  his 
walk. 

Moral  energy  is  not  the  true  source  of  the  power  of 
resisting  fatigue.  In  most  cases  what  makes  the  differ- 
ence between  the  power  for  work  of  two  persons  is  less 
the  manner  in  which  they  are  physically  and  morally 
endowed  than  the  preparation  they  have  undergone  or 
the  life  they  have  led  ;  it  is  less  a  matter  of  tempera- 
ment than  of  acquired  aptitude. 

Amongst  domestic  animals  there  are  great  differences 
in  the  matter  of  fitness  for  work.  Wild  animals,  on 
the  contrary,  have  sensibly  the  same  power  of  enduring 
prolonged  muscular  effort.  Two  wolves  of  the  same  age 
have  nearly  the  same  speed  and  the  same  staying  power. 
Two  dogs,  even  from  the  same  litter,  often  show  con- 
siderable differences  in  their  power  of  resisting  fatigue. 
The  differences  which  domestic  animals  present  among 
themselves  as  regards  the  power  of  resisting  fatigue  is 
due  to  the  num.erous  variations  in  their  mode  of  life  to 
which  domestication  leads.  The  remarkable  equality  of 
wild  animals,  from  the  same  point  of  view,  is  due  to  the 
similarity  of  their  conditions  of  existence. 

What  are  the  conditions  producing  power  of  resisting 
fatigue  ?  This  question  was  long  ago  answered  empi- 
rically, and  by  facts.  We  know  that  the  practice  of  cei- 
tain  muscular  exercises  associated  with  certain  rules  of 
diet,  called  as  a  whole  trainings  very  quickly  induces  in 
men  and  other  animals  the  power  of  supporting,  without 
ill  effect,  a  violent  and  prolonged  exercise  which,  without 
such  preparation,  would  have  had  serious  consequences  to 
the  system.  We  also  know  that,  the  power  of  resistance 
due  to  training  is  lost  as  soon  as  the  animal  returns  to 
the  mode  of  life  which  he  had  for  a  time  given  up. 

Why  does  a  man  who  daily  performs  muscular  exer- 


POWER   OF   RESISTING  FATIGUE.  1P3 

CISC  acquire,  by  the  very  fact  of  working,  the  power  (  f 
working  without  fatigue  ?  A  very  simple  answer  is 
usually  given  to  this  question  :  it  is  said  that  the  man 
has  become  "accustomed  "  to  fatigue.  Those  who  wish 
to  give  their  explanation  a  more  scientific  ring  speak  of 
the  "  habituation  "  of  the  body  to  work. 

If  we  consider  fatigue  as  pain,  it  is  absurd  to  say  that 
a  man  becomes  accustomed  to  fatigue.  A  man  cannot 
become  accustomed  to  pain  so  as  not  to  feel  it  any 
longer.  Ask  a  man  suffering  from  severe  neuralgia  if  he 
suffers  less  because  he  has  been  suftering  for  a  long  time  ! 
It  is  not  right  to  say  that  a  man  accustomed  to  work 
"  supports  "  fatigue  well.  He  has  not  to  support  it  at  all, 
for  it  is  not  produced. 

A  well-trained  man  resists  fatigue  easily,  not  because 
he  despises  the  painful  sensation  which  habitually  accom- 
panies work,  in  the  way  in  which  the  Stoics  despised 
pain,  but  because  this  sensation  is  not  produced  in  him, 
or  at  least  is  produced  in  a  very  slight  and  easily  bear- 
able degree.  Thus  the  power  of  resisting  fatigue  is  not 
due  to  the  greater  tolerance  of  the  worker,  but  to  the 
diminished  intensity  of  the  discomfort  to  be  borne. 

The  power  of  resisting  fatigue  is  due  to  a  material 
change  produced  by  an  exercise  which  is  often  practised 
in  the  structure  of  the  organs  by  which  the  work  is  per- 
formed. When  we  say  that  a  m.an  is  "  hardened  "  to 
fatigue,  this  expression  m.ust  be  taken  in  its  literal,  never 
in  its  figurative  sense.  Work  produces  in  all  the  tissues 
of  the  body  changes  of  nutrition  which  make  them  more 
resistant,  firmer,  which  in  a  sense  arms  them  against 
shocks  and  friction,  and  insures  them  against  the  acci- 
dents of  work.  Prolonged  repose,  on  the  other  hand, 
makes  the  tissues  softer  and  more  vulnerable. 

A  gardener  who  works  from  morning  till  night  does 
not  hurt  his  hands  by  holding  the  spade  ;  a  scholar  who 
performed  the  same  exercise  for  an  hour  would  complain 
that  his  hands  were  painful.  Has  the  gardener,  then, 
more  energy  than  the  savant  ?  No  ;  he  merely  has  a 
thicker  skin.  No  blisters  form  on  the  callous  skin  which 
covers  the  parts  of  his  hands  habitually  in  contact  with 


1 84  PHYSIOLOGY  OF  BODILY  EXERCISE. 

the  tool.  This  is  as  evident  as  it  is  po«=sible.  It  gives  ns 
an  example  of  what  occurs  daily  in  the  organism  under 
the  influence  of  work.  Every  organ  which  works  under- 
goes a  material  change,  from  which  results  a  greater  fit- 
ness for  performing  work  without  being  pained  by  it 

Through  daily  exercise  the  muscles  become  harder 
and  more  elastic  :  they  are  thus  more  ready  to  resist 
shocks  and  strains,  more  fitted  also  to  protect  from  ex- 
ternal violence  the  sensitive  parts  which  they  cover  : 
nerve  filaments  and  internal  organs.  A  well-trained 
boxer  no  longer  feels  a  blow  with  the  fist,  his  flesh  has 
become  so  hard  that  it  is  not  injured  by  the  blow  ;  it  is 
the  fist  of  his  adversary  which  is  injured  by  striking  it. 

Exercise  does  not  merely  harden  the  skin  and 
the  muscles  ;  it  consolidates  all  the  organs  of  work. 
Domestic  animals  which  do  hard  w^ork  acquire  tou^h 
and  solid  tendons.  Amongst  wild  beasts  there  is  a 
great  difference  between  frugivorous  and  carnivorous 
animals.  The  flesh  feeders  which  live  by  the  chase 
and  are  always  on  foot  to  watch  for  and  pursue  their 
prey,  show  to  an  extreme  degree  the  type  of  the  trained 
animal.  Their  tendons,  the  fasciae  which  sheathe  their 
muscles,  and  the  muscles  themselves,  are  as  hard  as 
wood.  To  get  an  idea  of  the  hardness  of  the  tissues 
in  a  hunting  animal,  it  is  necessary  to  dissect,  as  we 
have  done,  an  old  wolf.  The  knife  will  hardly  cut  the 
tendons  and  fibrous  tissue.  Similarly  with  birds  w^hich 
live  by  the  chase,  the  falcon  and  the  hawk.  All  the 
animals  which  lead  a  life  of  rapine  and  brigandage  are 
in  continual  movement,  and  the  uninterrupted  exercise 
changes  the  structure  of  their  organs  so  as  to  give  them 
a  surprising  powxr  of  resistance. 

The  other  wild  animals  w^hich  live  on  plants  have  a 
quite  different  organization.  The  hare,  the  partridge, 
the  quail,  saving  the  flights  given  them  from  time  to 
time  by  the  hunter,  pass  their  time  in  feeding  on  a 
nutriment  which  abounds  at  every  turn  ;  they  sleep 
peacefully  and  do  very  little.  And  their  flesh  is  fat  and 
tender,  their  muscles  soft  and  saturated  with  savoury 
juices.     We  eat  the  hare  and  the  quail,  their  flesh  melts 


POWER  OF   RESISTING   FATIGUE.  1 85 

in  our  mouth  ;  we  do  not  eat  the  flesh  of  the  falcon  or 
the  wolf  ;  we  should  leave  our  teeth  in  it. 

It  is  the  difference  of  work  which  causes  the  marked 
differences  of  structure  observed  in  animals.  The  same 
differences  are  to  be  seen  in  man.  If  we  dissect  a  man 
who  throughout  life  has  performed  violent  exercises  or 
hard  work,  we  are  struck  by  the  remarkable  power  of 
resistance  and  by  the  solidity  of  all  the  tissues  concerned 
m  movement.  We  easily  understand  how  these  large 
and  firm  muscles,  these  thick  and  solid  fasciae,  these 
tendons,  dry  and  hard  as  steel,  could  resist  without 
suffering  all  the  shocks  of  work. 

The  bones  themselves  become  adapted,  by  an  increase 
in  size  and  density,  to  the  more  energetic  work  of  the 
muscles  attached  to  them.  The  bones  of  horses  which 
have  done  violent  work  in  a  circus  for  some  years  have 
been  weighed,  and  compared  with  those  of  horses  of  the 
same  build  which  have  spent  their  life  quietly  at  grass  ; 
the  skeletons  of  the  circus  horses  were  much  heavier, 
their  bones  were  harder  and  firmer.  In  man  also,  mus- 
cular work  causes  an  appreciable  change  in  the  nutrition 
of  the  bones.  It  is  easy  to  say,  by  simple  examination 
of  a  human  skeleton,  whether  the  person  to  whom  it 
belonged  has  led  a  life  of  muscular  activity,  or  if  he  has 
lived  in  physical  idleness.  The  bony  points  to  which 
the  muscular  fibres  are  attached  are  smooth  and  regular 
if  the  muscles  have  been  inactive  :  on  the  contrary  if 
the  man  was  active,  the  points  of  muscular  attachment 
are  prominent,  and  there  are  roughnesses  which  furnish 
a  stronger  attachment  to  the  fibres. 

Besides  these  changes  which  are  so  easily  discovered 
in  the  organism  as  a  result  of  work,  there  are  certainly 
many  others  of  which  we  know  less.  There  is  no  ab- 
surdity in  thinking,  for  instance,  that  the  epithelium  of 
the  synovial  membranes  must  undergo,  under  the  influ- 
ence of  the  energetic  friction  caused  by  work,  changes 
analogous  to  those  occurring  in  the  thickened  epidermis, 
and  thus  become  more  able  to  support  severe  pressure 
without  injury.  Similarly,  everything  leads  us  to  believe 
that  the  nerve  filaments  which  pass  through  the  muscles 


1 85  PHYSIOLOGY  OF   BODILY  EXERCISE. 

receive  a  similar  protection.  A  nerve  is  surrounded  by 
a  fibrous  sheath,  the  neurilemma  ;  the  elements  forming 
this  protective  envelope  probably  participate  in  the 
more  energetic  nutrition  which  goes  on  in  all  the  fibrous 
tissues  in  consequence  of  work  ;  thus,  doubtless,  may 
be  explained  the^  steady  decrease  of  the  pain  felt  in  a 
region  of  work.  The  re|  e  ited  muscular  contractions 
become  less  painful  because  the  nerve  filaments  which 
traverse  the  muscle  are  better  protected  against  the 
pressures  and  frictions  by  a  firmer  neurilemma. 

To  sum  up,  muscular  exercise  has  a  considerable  in- 
fluence on  the  process  of  nutrition,  and  it  is  to  this 
influence  that  are  due  the  changes  which  occur  in  the 
conformation  of  a  person  whose  muscles  are  habitually 
in  action. 

The  body  of  a  man  or  an  animal,  under  the  influence 
of  a  regular  exercise  progressively  increased,  is  modified 
in  a  manner  which  makes  the  performance  of  the  work 
more  easy.     Herein  lies  the  secret  of  "  habituation." 


CHAPTER  îî. 

MODIFICATION   OF  THE  ORGANS   BY  WORK. 

Function  makes  Structure— Disappearance  of  Organs  when  their 
Function  has  Ceased;  Maintenance  of  Organs  by  Persistence 
of  Function— Why  Gymnasts  remain  Supple  even  in  Old  Age 
—Modification  of  Motor  Organs  by  Exercise— Modification  _  of 
Organic  Apparatus  associated  with  Movement  ;  Amplification 
of  the  Lungs— Changes  in  the  Living  Tissues  due  to  Work-- 
More  active  Assimilation  ;  Growth  of  Muscles— More  rapid 
Dissimilation  ;  Diminution  of  Reserve  Materials— Increase_  of 
Strength  through  Growth  of  the  Muscular  Tissues— Lessening 
of  Fatigue  ;  It  is  due  to  the  gradual  Disappearance  of  the 
Reserve  Materials— How  this  Result  is  Explained— Fat  causes 
Breathlessness— By  what  Mechanism?  Insufficiency  of  ad- 
mitted Explanations— Theor)'  of  Trainers  :  the  "  Internal  Fat." 
Objections  to  this  Theory— Practical  Observation— Reserve  Fat 
and  Constitutional  Fat— Fat  Runnen— Easy  Dissimilation  of 
Reserve  Fats,  causes  Breathlessness  by  Excessive  Production 
of  Carbonic  Acid— Reserve  Proteids  and  Consecutive  Fatigue 
— Disappearance  of  Stiffness  of  Fatigue  in  Connection  with  the 
Disappearance  of  Urinary  Deposits  after  Exercise— Personal 
Observations  of  Fatigue. 

I. 

The  physiologists  say  ihd.t  >" function  makes  structiire^^ 
This  means  that  the  human  body  adapts  itself,  by 
changes  of  conformation,  to  any  frequently  repeated 
action. 

It  is  always  difficult  to  get  a  clear  idea  of  anything 
enunciated  in  a  general  and  abstract  form.  We  will  try 
to  give  definite  form  to  the  idea  we  have  mentioned  by 
an  example.  Suppose  that  a  man  has  suffered  from  a 
dislocation  at  the  shoulder-joint,  the  head  of  the  humerus 
has  slipped  out  of  the  articular  cavity,  and  is  somewhere 
in  the  neighbourhood  of  it.   If  not  reduced,  the  luxation 


1 88  PHYSIOLOGY  OF   BODILY  EXERCISE. 

will  not  heal  of  itself,  the  head  of  the  bone  will  not 
return  into  the  hollow  from  which  it  has  escaped,  the 
limb  will  be  motionless  in  the  false  position  due  to  the 
accident,  and  after  some  months  anchylosis  occurs.  If 
the  surgeon  is  now  called  in,  it  is  too  late  to  replace  the 
luxated  bone  ;  and  he  can  only  give  this  advice,  to  move 
the  arm  as  much  as  possible  in  the  hope  of  restoring  its 
powers.  In  fact  by  regular  daily  movement  of  the  arm, 
its  functions  may  be  re-established,  and  although  in  an 
abnormal  position,  it  once  more  becomes  capable  of 
action. 

We  see  patients  in  whom  the  head  of  the  humerus 
has  lodged  between  the  clavicle  and  the  upper  ribs, 
an  inch  away  from  the  normal  joint  cavity,  and 
who  yet  recover  by  daily  exercise  of  the  arm,  a  great 
part  of  the  movements  of  the  limb.  If  we  have  the 
opportunity  of  making  an  autopsy  in  such  a  case,  we 
find  that  the  head  of  the  humerus  has  hollowed  out  a 
new  cavity  for  itself  at  the  expense  of  the  clavicle  and 
ribs  with  which  it  is  in  contact.  If  the  dislocation  is 
old,  and  the  patient  has  done  much  work  with  the  limb 
since  the  accident  accurred,  the  new  joint-cavity  has  all 
the  appearance  of  a  normal  one.  A  synovial  membrane, 
articular  cartilages,  fibrous  capsule,  in  fact  all  the 
elements  which  form  a  joint,  have  developed  in  an  ab- 
normal position. 

This  is  known  as  a  false  joint.  A  joint,  an  organ 
indispensable  to  movement,  can  then  be  created  by 
movement  itself. 

Thus  "function  makes  structure."  But  there  is  a 
corollary  to  this  law,  which  may  be  thus  formulated, 
"  the  cessation  of  the  function  leads  to  the  disappearance 
of  the  structure." 

In  the  case  just  quoted  for  instance,  the  articular 
cavity  from  which  the  head  of  the  humerus  has  escaped, 
being  no  longer  the  seat  of  movement,  soon  loses  its 
shape  and  ordinary  structure  ;  the  synovia  which  served 
to  lubricate  the  surfaces  of  the  joint,  being  no  longer  of 
use,  is  no  longer  secreted  ;  the  synovial  membrane  itself 
disappears  ;  further,  the  articular  cartilages  are  gradually 


MODIFICATION   OF   THE   ORGANS   BY   WORK.      i8q 

replaced  by  bone,  and  after  a  time  the  whole  articular 
cavity  fills  up  and  disappears.  The  cessation  of  func- 
tion has  caused  the  disappearance  of  the  structure.  The 
law  of  the  intimate  connection  of  the  existence  of  an 
organ  with  that  of  its  function  is  nowhere  more  evident 
than  in  muscular  work.  It  not  only  applies  to  the 
formation  of  a  new  organ  by  a  new  function,  but  also 
to  the  improvement  of  an  already  existing  organ  by  the 
fact  of  more  frequent  use. 

The  phenomena  observed  in  a  man  who  performs 
regular  muscular  work  fully  bears  out  the  law  we  have 
just  enunciated.  Muscular  work  tends  to  modify  the 
nutrition  of  all  the  motor  organs  and  to  give  to  them  a 
structure  which  is  favourable  to  the  performance  of 
movements.  If  we  review  all  the  organs  which  concur 
in  the  performance  of  work,  we  see  that  all  are  subject 
to  this  physiological  law  of  adaptation  to  function,  or, 
in  other  words,  of  improvement  by  work.  We  also  see, 
by  observing  the  converse  phenomena,  that  defective 
function  of  an  organ  leads  to  its  decline  and  to  arrest  of 
its  development. 

Muscles  increase  in  size  through  work,  at  the  same 
time  as  their  fibres  become  free  from  any  clogging 
materials,  and  are  freed  from  the  fat  which  hinders  con- 
traction. Repose,  on  the  other  hand,  causes  atrophy  of 
the  muscular  tissue,  and  the  muscle  which  remains 
inactive  too  long  becomes  infiltrated  with  fat. 

The  joints  are  the  parts  of  the  body  whose  perfect 
action  is  of  the  utmost  importance  for  the  proper  per- 
formance of  movement.  And  there  are  none  which  feel 
more  fully  the  influence  of  muscular  exercise.  To  learn 
this  we  must  compare  a  joint  which  has  long  been 
motionless  with  one  which  has  undergone  repeated 
movements.  That  which  has  been  much  at  work  has 
acquired  a  marvellous  ease  of  movement  ;  that  which 
has  remained  inactive  becomes  in  the  end  anchylosed, 
that  is,  the  bones  forming  the  joint  become  ossified 
together.  Exercise  of  a  limb  preserves  the  mobility  of 
its  joints,  and  it  is  for  this  reason  that  gymnasts  preserve 
in  old  age  supple  movements  and   youthful   attitudes. 


190  PHYSIOLOGY  OF   BODILY   EXERCISE. 

Age  tends  to  cause  the  deposit  of  calcareous  salts  in  all 
the  tissues  of  the  economy  ;  the  arteries  of  the  old  man 
are  hard  and  deficient  in  elasticity  ;  his  fibrous  tissues 
tend  to  become  indurated,  and  his  ligaments  are  more 
and  more  ossified.  But  continual  movement  of  a  jx)int 
opposes  the  tendency  to  calcareous  degeneration  ;  work 
renders  anchylosis  and  calcareous  degeneration  of  the 
fibrous  tissues  impossible  ;  as  long  as  a  man  keeps  his 
muscles  at  work  he  remains  able  to  use  his  limbs.  The 
persistence  of  function  preserves  the  integrity  of  the 
organ. 

The  internal  organs,  under  the  influence  of  muscular 
exercise,  also  undergo  changes  which  favour  the  per- 
formance of  the  often-repeated  action. 

The  lungs,  the  air-cells  of  which  are  brought  more 
into  play  by  a  more  active  respiration,  expand,  and 
push  outwards  in  all  directions  the  osseous  walls  of  their 
prison  ;  the  thorax  expands,  the  ribs  are  raised,  and  the 
chest  assumes  a  very  characteristic  convex  shape.  All 
professional  gymnasts  show  a  kind  of  vaulting  of  the 
part  of  the  chest  corresponding  to  the  upper  ribs  and.  to 
the  clavicle.  Measurements  of  young  soldiers  at  the 
Gymnasium  at  Joinville  have  been  taken,  and  in  a  few 
months  an  increase  has  been  noted  of  several  centi- 
metres in  the  circumference  of  the  chest  under  the 
influence  of  muscular  exercise. 

It  is  easy  to  understand  how  respiration  must  be 
facilitated  by  this  increase  in  the  size  of  the  thorax.  A 
much  greater  volume  of  air  is  introduced  into  the  lungs, 
and  the  elimination  of  the  respiratory  waste-products 
takes  place  over  a  much  larger  field,  breathlessness 
during  exercise  diminishes. 

The  heart  hkewise  undergoes  a  change  in  size  and 
structure.  Its  muscular  fibres  become  larger,  and  the 
whole  tissue  becomes  firmer  and  denser  ;  it  frees  itself 
from  the  fat  which  oppressed  it,  and  diminished  the 
elasticity  of  its  fibres.  This  change  favours  the  per- 
formance of  exercise,  for  a  vigorous  heart  drives  the 
blood  more  energetically,  and  makes  'it  traverse  the 
capillaries    without    difficulty.      The    more     energetic 


MODIFICATION   OF   THE   ORGANS   BY   WORK.      I9I 

impulse  given  to  the  blood  opposes  the  engorgement  of 
the  pulmonary  capillaries  during  exercise,  and  this  puts 
out  of  count  a  very  potent  cause  of  breathlessness  ; 
passive  pulmonary  congestion. 

IL 

By  what  mechanism  does  muscular  exercise  lead  to 
the  changes  in  *the  organs  of  which  vv^e  have  given  a 
brief  sketch?  To  answer  this  question  we  must  go 
more  fully  than  we  have  done  into  the  details  of  the 
changes  undergone  by  an  organism  which  works  every 
day,  and  study  the  influence  of  exercise  on  the  nutrition 
of  the  living  tissues. 

The  first  effect  of  muscular  exercise  is  to  render  the 
vital  combustions  more  active,  and  consequently  to 
diminish  the  mass  of  the  tissues  on  which  these  com- 
bustions feed.  But  it  also  causes  a  more  active  process 
of  assimilation,  that  is,  a  process  of  adding  to  the 
existing  tissues  new  molecules  derived  from  the  products 
of  digestion.  Hence  the  second  process  compensates 
for  the  effects  of  the  first,  and  the  losses  sustained  _  in 
the  act  of  work  are  repaired  by  new  acquisitions  which 
are  also  a  consequence  of  work. 

But  these  losses  and  gains,  if  balanced  in  quantity, 
do  not  take  place  in  the  same  anatomical  elements. 
Certain  tissues  are  used  up  by  the  combustions  of 
muscular  exercise,  and  these  tissues  are  of  another  order 
to  those  which  benefit  by  the  increased  activity  of  the 
process  of  nutrition.  Under  the  influence  of  work  the 
muscles  increase,  while  fat  disappears.  Now  these 
muscles  are  the  organs  of  work,  and  their  greater 
development  increases  the  strength  of  the  subject.^  Fats, 
on  the  other  hand,  are  an  incumbrance,  useless  in  the 
mechanicTal  execution  of  movement,  and  able  to  hinder 
work  in  various  ways.  The  process  of  nutrition  is  then 
directed  by  muscular  v  ork  in  a  manner  which  renders 
the  individual  fitter  for  the  performance  of  work. 

When  we  examine  the  details  of  movement,  we  see 
that  at  each  muscular  contraction  an  increased  quantity 
of  blood  flows  to  the  muscle,  bathes  the  motor  fibres,  and 


192  PHYSIOLOGY  OF    BODILY  EXERCISE. 

remains  in  contact  with  them  for  a  long  time  ;  in  this 
way  the  elements  of  the  nutritive  fluid  can  be  deposited 
in  the  muscular  elements,  which  are  g^radually  increased 
in  size.  Fatty  tissue  undergoes  during  work  chemical 
changes  to  which  its  composition  renders  it  especially 
liable.  It  is  made  of  elements  which  have  a  great 
affinity  for  oxygen,  for  it  consists  of  carbon  and  hydro- 
gen. Now  oxygen  is  the  most  active  principle  of  vital 
combustions.  It  is  at  the  expense  of  the  hydrocarbons 
that  the  chemical  combinations  which  give  rise  to  vital 
heat  are  by  preference  carried  on.  At  every  muscular 
contraction  there  is  an  expenditure  of  heat  in  proportion 
to  the  force  of  the  contraction,  and,  according  to  the  most 
recent  theories,  it  is  by  the  combustion  of  fats  that  the 
heat  expended  by  muscles  at  work  is  supplied. 

If  we  endeavour  to  display  the  consequences  of  these 
facts  from  the  point  of  view  of  fitness  for  work,  we  shall 
find  that  the  progressive  disappearance  of  fat  and  the 
increase  in  the  size  of  the  muscles  are  two  conditions 
equally  favourable  to  work. 

The  increased  volume  of  the  muscular  tissues  leads  to 
a  proportionate  increase  in  strength.  We  know  that 
the  contractile  power  of  muscle  varies  directly  as  its 
cross  section. 

The  diminution  in  the  quantity  of  fat  facilitates  work, 
for  reasons  which  we  must  consider  in  some  detail. 

In  the  first  place,  the  disappearance  of  the  fatty 
masses  amongst  the  organs  lightens  the  body  and  facili- 
tates all  the  movements  concerned  in  changing  its  place, 
walkincr,  running,  and  jumping.  This  result  is  one  of  the 
most  important  and  most  desired  in  the  methods  of 
training  which  prepare  a  man  for  speed.  But  fat  does 
not  only  hinder  work  by  its  weight  :  it  is  a  cause  of  ex- 
cessive heating  of  the  body  during  muscular  exercise,  it 
is  opposed  to  the  ready  cooling  of  the  blood  owing  to  its 
low  power  of  conduction  :  the  body  surrounded  by  a 
layer  of  fat  tends  to  preserve  its  heat  as  if  it  were  enve- 
loped in  a  thick  layer  of  cotton  wool.  When  a  fat  man 
becomes  heated  by  work  it  is  with  difficulty  that  the  heat 
radiates  to  the  exterior,  through  the  layer  of  fat  with 


MODIFICATION   OF   THE   ORGANS   BY  WORK.       193 

which  he  is  covered,  and  tlie  blood  can  cool  but  slowly. 
We  may  observe  further  the  converse  of  this.  Very  thin 
animals  bear  cold  badly.  Race  horses  deprived  of  their 
fatty  covering"  by  training  are  very  liable  to  take  cold, 
and  cannot,  without  serious  danger,  dispense  with  warm 
wrappings  and  comfortably  appointed  stables. 

Finally  there  is  another  cause  of  fatigue  which  results 
fiom  the  accumulation  of  fat  in  the  system  :  it  is  the 
facility  with  which  this  tissue  undergoes  dissimilation. 

We  know  that  fat  is  the  type  of  the  reserve  tissues. 
The  object  of  these  substances  is  to  furnish  the  supple- 
mentary expenditure  of  heat  which  may  be  rendered 
necessary  by  an  increased  muscular  work  :  they  are  stores 
amassed  in  the  body,  and  always  ready  to  serve  as  fuel 
for  combustion.  We  may  say  that  these  substances  do 
not  form  an  integral  part  of  the  organism,  and  are  inter- 
mediaries between  the  organs  round  which  they  accumu- 
late, without  entering  into  their  intimate  structure,  and 
the  foods  from  which  they  are  derived,  and  form  as  it 
were  a  savings'  bank. 

The  reserve  materials,  being  destined  to  disappear, 
have  then  less  power  of  resistance  than  those  which  form 
the  fundamental  woof  of  the  organs  ;  hence  they  especi- 
ally are  attacked  by  the  vital  combustions.  A  man  very 
abundantly  supplied  with  fatty  tissues  expends  more 
heat,  for  an  equal  amount  of  work,  than  a  man  of  the 
same  weight  whose  build  is  lean,  and  who  is  very  muscu- 
lar. The  combustions  in  the  fat  man  seem  to  be  with 
difficulty  held  within  bounds,  and  the  quantity  of  heat 
produced  greatly  exceeds  that  which  is  expended  in  the 
work.  When  a  fat  man  has  lost  his  fat  we  may  say  that 
the  yield  of  his  muscles  has  increased  ;  their  contraction 
is  caused  by  more  moderate  combustions,  and  the  ex- 
penditure of  heat  tends  to  approach  more  nearly  the 
figure  of  the  mechanical  equivalent. 

But  other  elements  of  fatigue  tend  to  disappear  in  a 
man  who  becomes  tbin,  in  proportion  as  his  expenditure 
of  heat  diminishes  ;  these  are  the  products  of  dissimila- 
tion. These  products  vary  much  according  to  the  nature 
of  the  chemical  compounds  which  are  the  source  of  the 


194  PHYSIOLOGY  OF   BODILY   EXERCISE. 

heat  produced  ;  they  are  still  but  little  known,  but  we 
cannot  help  thinking  that  their  composition  depends 
upon  that  of  the  tissues  giving  rise  to  their  formation. 
We  must  believe,  for  instance,  that  the  fatty  tissues,  built 
up  chiefly  of  carbon  and  hydrogen,  must  furnish  by  their 
combustion,  by  their  combination  with  oxygen,  much 
carbonic  acid  and  water.  This  opinion  is  confirmed  by 
observation,  which  shows  us  how  fat  people  lose  their 
breath,  other  things  being  equal,  much  more  quickly  than 
thin  ones,  and  also  that  they  perspire  much  more  freely. 

The  breathing  of  very  fat  men  and  animals  becomes 
easier  in  proportion  as  training  removes  the  excess  of 
fat  from  their  bodies.  All  trainers  know  well  that  this 
improvement  is  not  merely  due  to  the  loss  in  the  total 
weight  of  the  body,  and  the  lessened  work  which,  in  run- 
ning for  instance,  has  then  to  be  performed.  In  fact,  a 
well-trained  horse,  and  also  a  prize-fighter  in  perfect 
"  condition  "  may  weigh  as  much  as  they  did  at  the  out- 
set. They  have  acquired  muscular  tissue  which  compen- 
sates for  the  loss  of  fat. 

We  believe  that  this  freedom  from  breathlessness  is 
largely  because  the  absence  of  the  hydrocarbon  reserves 
leads  to  the  elimination  of  the  products  of  combustion  of 
which  hydrogen  and  carbon  form  the  basis,  and  particu- 
larly to  the  lessened  formation  of  carbonic  acid.  A  well- 
trained  man  must  produce,  by  an  equal  quantity  of  work, 
less  carbonic  acid  than  he  did  before  training  began. 

In  training  race-horses,  great  importance  is  attached  to 
causing  the  disappearance  of  fat,  and  it  is  well-known 
that  by  diminishing  the  quantity  of  this  tissue,  the  horse 
is  enabled  to  breathe  more  easily.  But  trainers  give  a 
fantastical  explanation  of  this  fact  :  they  pretend  that 
the  "  internal  "  fat  hinders  the  movements  of  the  lungs, 
and  that  by  its  removal  these  organs  have  freer  play. 
This  explanation  is  quite  unsatisfactory.  Firstly,  the 
lung  is,  of  all  the  viscera,  that  least  subject  to  fatty 
deposit.  Further,  the  immunity  from  breathlessness 
during  work  is  seen  in  all  trained  persons  alike,  even  in 
those  who  have  more  fat  about  them  than  many  untrained 
individuals. 


MODIFICATION   OF   THE  ORGANS   BY  WORTC       I95 

In  fact  there  are  persons  who,  accordini^  to  the  tech- 
nical expression,  "  train  fat,"  that  is  to  say,  in  spite  of  the 
work,  and  in  spite  of  the  power  they  gain  of  enduring  it, 
retain  a  large  quantity  of  fat.  In  these  persons  a  certain 
amount  of  fat  forms  an  integral  part  of  the  system,  and 
this  cannot  be  lost  without  at  the  same  time  lessening 
their  power  of  resistance.  This  fact  is  well  known  to 
men  who  have  to  do  with  horses,  and  is  pointed  out  in 
the  excellent  work  of  Stonehenge  on  the  training  of 
race-horses.  Many  gain  great  speed,  and  breathing- 
power,  without  losing  their  fat  as  completely  as  others. 

If  we  go  into  the  society  of  men  given  to  athletic  sports, 
we  see  that  the  same  thing  holds  true  of  men  as  of 
horses,  and  it  is  not  rare  to  meet  with  very  agile  athletes, 
and  even  professional  runners,  who  show  at  the  same 
time  considerable  amount  of  fat,  and  very  free  respiration 
without  tendencies  to  breathlessness.  By  the  side  of 
these  men  we  may  see  others  who  hardly  have  under 
their  skin  two  or  three  millimetres  of  fatty  tissue,  and 
yet — not  being  trained — get  out  of  breath  very  much 
sooner  than  the  persons  who  are  at  once  fat  and  in 
training. 

If  the  fat  were  only  a  hindrance  by  reason  of  the 
space  it  occupies,  this  would  not  be  the  case  ;  but  it 
acts  chiefly  by  the  ready  tendency  it  has  to  undergo 
dissimilation,  or,  in  other  words,  by  the  ease  with  which 
it  is  burned  during  work.  But  fat  does  not  always 
burn  at  the  same  rate.  In  certain  temperaments  fat 
forms  an  integral  part  of  the  organic  structure  ;  it  is  a 
constitutional  tissue,  it  has  so  to  speak  freedom  of  the 
city  amongst  the  anatomical  elements  which  accompany 
it.  In  other  persons,  on  the  contrary,  thinness  is  the 
dominant  attribute  of  their  temperament,  and  all  the  fat 
they  possess  is  a  superadded  element,  only  forming  part 
of  the  constitution  by  a  provisional  title,  and  consequently 
destined  to  disappear  very  readily.  In  some,  fat  is  a 
*•  constitutional  "  tissue,  in  others  it  is  merely  a  reserve^ 
a  provision  to  be  consumed  at  the  first  demands  of  the 
system. 

1 1  is  then  opposed  to  the  facts  of  observation  to  speak 


ïç6  PHYSIOLOGY  OF   EODILY   EXERCISE. 

of  "  internal  fat  "  which  disappears,  and  of"  external  fat  " 
which  remains.  Fat  is  equally  distributed  throughout 
the  system  ;  and  if  any  cause,  such  as  work,  brings  about 
a  diminution  in  its  quantity,  the  parts  which  work  most 
are  earliest  free  from  it. 

When  we  see  fat  men  take  to  fencing  in  order  to 
get  thin,  we  notice  that  in  them  the  internal  fat  is  far 
from  being  the  first  to  disappear  ;  the  abdomen  is  the 
region  w^hich  retains  with  most  tenacity  its  supply  of 
fat.  There  can  be  nothing  more  awkward  than  the 
shape  of  the  body  of  a  man  in  this  ungrateful  period 
when  the  fat  has  disappeared  from  his  arms,  his  chest, 
and  his  legs,  while  his  belly  remains  as  large  as  ever. 
The  regions  which  have  been  made  to  work  in  fencing 
have  lost  their  fat  ;  the  arms  and  legs  appear  slender, 
and  the  chest,  which  has  been  freed  by  the  work  of 
the  pectoral  muscles,  appears  shrunken  by  comparison 
with  the  abdomen  which  has  remained  of  its  original 
size.  It  is  only  by  continuing  his  exercise  for  some 
weeks  still,  that  the  fat  man  is  able  to  gain  what  he 
above  all  desires,  the  diminution  in  the  size  of  his  belly. 
Now  the  respiration  has  become  easy  and  breathlessness 
has  diminished  long  before  the  disappearance  of  the 
fatty  masses  of  the  abdomen,  the  persistence  of  which 
must  singularly  hinder  the  vertical  enlargement  of  the 
thorax. 

The  diminution  of  breathlessness  in  the  trained  man 
or  horse,  is  much  less  due  to  the  greater  freedom  of  the 
lungs  owing  to  the  removal  of  the  fat  in  their  neighbour- 
hood, than  to  the  lessened  production  of  carbonic  acid 
w^hich  results  from  the  disappearance  of  the  provisions 
of  combustible  tissue  which  give  rise  to  too  great  a 
quantity  of  this  gas. 

Persons  who  practise  running  very  soon  gain  the 
power  of  not  losing  breath,  for  running  is  the  exercise 
which  most  quickly  causes  the  disappearance  of  the  fatty 
tissues. 

The  combustion  of  the  fatty  tissues  during  work  gives 
a  satisfactory  explanation  why  the  practice  of  muscular 
exercise    lessens    the    tendency    of   a    man  to    become 


MODIFICATION   OF   THE   ORGANS   BY   WORK.       I97 

breathless.  The  man  in  training  has  no  longer  in  his 
system  the  elements  capable  of  producing  this  excessive 
quantity  of  carbonic  acid,  as  was  the  case  before  he 
began  regular  exercise.  The  disappearance  of  the  tissues 
rich  in  hydrogen,  explains  also  the  lessened  perspiration 
of  the  man  in  training.  Sweat  mostly  consists  of  water, 
and  the  burning  of  a  substance  rich  in  hydrogen  must 
tend  to  cause  the  formation  of  an  excess  of  aqueous 
secretion. 

Breathlessness  is  not  the  only  form  of  fatigue,  just 
as  fats  are  not  the  only  reserve  materials.  There  are, 
produced  by  work,  nitrogenous  products  of  combustion 
which  cannot  be  derived  from  fatty  substances.  There 
are,  among  the  reserve  materials,  proteid  substances,  and 
it  is  from  them  that  the  nitrogenous  substances  excreted 
by  the  urine  are  derived,  which  diminish  when  the 
organism  has  for  some  time  assiduously  practised 
muscular  exercise. 

These  substances  play  the  same  part  in  the  production 
of  stiffness  as  belongs  to  fats  in  the  production  of  breath- 
lessness. Fat,  in  being  burned,  gives  rise  to  carbonic 
acid  and  other  products  rich  in  carbon  and  hydrogen  ; 
proteids,  in  being  burned,  produce  a  whole  series  of 
nitrogenous  compounds  of  which  uric  acid  and  the 
various  extractives  are  the  type.  We  believe — and  we 
hope  that  we  have  proved  it  by  sufficiently  cogent 
arguments  * —  that  the  nitrogenous  waste-products  of 
combustion  which  are  formed  during  work,  and  which 
stay  sometimes  in  the  blood  when  work  is  done,  are  the 
cause  of  the  general  disturbances,  febrile  or  non-febrile, 
which  constitute  consecutive  fatigue  or  stiffness. 

In  the  man  accustomed  to  work  there  are  no  disorders 
following  exercise.  This  is  one  of  the  most  remarkable 
results  of  training,  and  would  be  quite  inexplicable  unless 
we  were  to  admit  that  daily  exercise  causes  the  dis- 
appearance from  the  body  of  the  organic  substances  to 
which  the  phenomena  of   consecutive  fatigue  are    due. 

•  See  pages  m  ef  seq. 


198  PHYSIOLOGY  OF   EODILY  EXERCISE. 

We  believe  that  these  substances  are  the  nitrogenous 
reserves  contained  in  muscle.  We  think  that  these 
nitrogenous  reserves  are  contained  in  the  muscles  them- 
selves ;  observation  shows  that  men  accustomed  to  one 
definite  kind  of  exercise  have  no  immunity  from  fatigue, 
and  can  experience  the  general  effects  of  stiffn^jss,  if  they 
suddenly  lake  to  another  exercise,  bringing  into  play 
muscles  which  have  not  yet  been  modified  by  work  and 
which  have  not  yet  lost  their  reserve  materials. 

Exercise  modifies  the  muscle  then  not  only  by  in- 
creasing the  size  of  its  elements,  but  also  by  changing  its 
structure,  by  eliminating  from  the  organ  not  only  fat, 
but  also  the  nitrogenous  substances  -capable  of  giving 
rise  to  superabundant  waste-products  of  combustion, 
which  cause  auto-intoxication  and  general,  consecutive 
fatigue. 

Thus  the  more  we  analyse  the  phenomena  of  work, 
the  more  we  see  that  the  frequent  repetition  of.  muscular 
movement  produces,  in  the  nutrition  of  the  living  tissues, 
material  changes  which  are  able  to  shelter  the  system 
from  the  various  disorders  of  fatigua 


CHAPTER    III. 

MODIFICATION   OF  FUNCTIONS   BV  WORK. 

Increase  in  the  Contractile  Force  of  Muscle — Probable  increasein 
the  Power  of  Conduction  of  Nerves  — Improvement  in  Faculties 
of  Co-ordination  of  Movement— Education  of  the  Muscular 
Sense— Domination  of  Reflex  Actions  by  the  Will  ;  Regulation 
of  the  Respiratory  Movements— Changes  produced  in  the  Ner- 
vous System  by  Muscular  Exercise — Material  Changes  in  the 
Nervous  Tissue  :  Are  they  purely  hypothetical  ? — An  observa- 
tion of  Luys  — Funct  onal  Changes  in  the  Nervous  System — 
The  Memory  of  the  Spinal  Cord  ;  its  Use  in  the  Performance  of 
often  Repeated  Actions  —  Psychical  Modifications  due  to 
Habituation  to  Work  —  Skill  —  Physical  Courage— Incredible 
Energy  of  Prize-fighters. 

We  have  studied  the  material  changes  which  take  place 
in  the  system  in  consequence  of  work  ;  we  have  just  seen 
how  exercise,  powerfully  influencing  the  process  of  nu- 
trition, has  the  power  of  changing  the  organs  and  of 
profoundly  altering  the  structure  of  the  tissues  of  the 
body.  A  man  used  to  work  shows  important  peculiarities 
in  his  external  conformation,  and  has  further  v^ry  charac- 
teristic ones  in  his  internal  structure.  All  the  wheels  of 
the  human  machine  have  been  gradually  adapted  to  the 
performance  of  the  great  quantity  of  work  daily  demanded 
from  them,  and  have  undergone  a  material  improvement 
which  renders  them  more  fit  for  their  function. 

Under  the  influence  of  exercise  man  is  physically 
transformed,  and  we  may  sum  up  in  a  few  words  the 
changes  which  have  taken  place  in  his  system,  in  passing 
from  an  inactive  mode  of  life  to  habits  of  work.  We 
may  say  that  all  parts  of  the  organism  capable  of  favour- 
ing the  performance  of  work  have  been  developed,  and 
all  the  materials  which  could  be  a  cause  of  hindrance  in 
the  performance  of  movements  have  been  diminished  in 
quantity  and  tend  to  disappear. 


200  PHYSIOLOGY  OF  BODILY  EXERCISE. 

From  these  two  orders  of  organic  modifications  there 
result  two  different  powers  acquired  by  habituation  to 
work  :  power  of  producing  more  energetic  movements, 
owing  to  the  greater  development  of  the  motor  organs  ; 
power  of  better  enduring  prolonged  muscular  efforts, 
owing  to  the  disappearance  of  the  reserve  materials,  the 
products  of  the  dissimilation  of  which,  when  too  abundant, 
lead  to  auto-intoxication  of  the  body,  the  most  important 
cause  of  the  phenomena  of  fatigue. 

The  material  changes  which  take  place  in  the  human 
body  when  work  is  regularly  performed,  can  explain  in 
great  part  the  increase  in  strength  and  in  power  of 
resisting  fatigue.  But  we  should  have  an  incomplete 
idea  of  the  benefits  due  to  habituation  to  work  if  we  did 
not  take  into  consideration  another  advantage  gained  by 
a  man  who  exercises  his  muscles  ;  it  is  the  improvement 
in  all  the  functions  which  take  part,  directly  or  indirectly, 
in  the  performance  of  work. 

I. 

Under  the  influence  of  well-planned  daily  exercise  the 
muscles  do  not  only  become  larger  and  firmer,  their 
power  of  contraction  alio  increases.  "  The  muscles  of 
a  man  in  training  contract  with  extraordinary  force 
under  the  influence  of  the  electric  current  "  *  said  Royer- 
Collard  many  years  ago  in  his  Paper  on  the  training  of 
English  prize-fighters.  Muscular  fibre  gains  by  exercise 
an  increase  of  its  power  of  contraction  and  can  obey 
more  vigorously  the  orders  of  the  will,  as  well  as  the 
stimuli  from  an  electric  battery.  We  observe  that  two 
muscles  being  of  equal  size,  the  muscle  which  is  in  the 
habit  of  contracting  is  stronger  than  the  one  which  has 
long  remained  inactive. 

The  same  improvement  is  observed  in  the  respiratory 
function  under  the  influence  of  work.  The  lungs  have 
not  only  been  increased  in  volume  by  exercise  ;  they 
have  further  gained  a  greater  power  of  performing  their 
movements  with  calmness  and  regularity  amidst  the 
violent  disturbances  in  the  system  which  are  caused  by 

*  Royer-CoUard.     Paper  read  before  the  Academy,  1842. 


MODIFICATION    OF   FUNCTIONS   BY  WORK.        201 

exercise.  In  a  man  accustomed-  to  violent  exercise  the 
breathing  long  maintains  its  regular  rhythm,  v.'hcreas  it 
is  quickly  disturbed  by  work  in  a  man  usually  inactive. 

The  heart,  besides  gaining  by  well-directed  exercise  a 
structure  more  favourable  to  work,  through  being  freed 
from  fat  with  which  it  may  be  charged,  also  learns  to 
work  more  regularly.  It  tends  to  lose  that  excessive 
excitability  which,  in  the  man  who  is  a  novice  in  exer- 
cise, promptly  disturbs  its  regular  action  on  the  slightest 
change  in  arterial  tension,  the  slightest  rise  in  the  tem- 
perature of  the  blood  :  it  no  longer  becomes  uncontrolled 
when  violent  exercise  is  performed. 

A  comparison  may  be  useful  to  render  these  facts 
more  clear,  rather  than  to  explain  them — for  no  satis- 
factory physiological  explanation  has  hitherto  been 
given.  A  man  who  is  accustomed  to  work  improves  his 
organs,  and  becomes  like  a  workman  who  does  his  work 
w^th  better  tools.  But  the  workman  learns  from  day  to 
day  to  use  his  tools  better,  and  in  the  end  makes  the 
best  possible  use  of  them.  Similarly  the  man  who  exer- 
cises his  body  every  day  becomes  better  able  to  use  his 
organs,  and  gets  more  work  out  of  them  through  making 
them  serve  him  better. 

•The  purely  functional  improvements  which  take  place 
in  the  work  of  organs  through  exercise  are  nowhere  so 
striking  as  in  the  performance  of  movements. 

Every  movement,  even  that  apparently  most  localised, 
is,  as  we  have  explained  in  detail,  an  action  necessitating 
the  concourse  of  several  mmscles,  some  synergic,  others 
antagonistic.  It  is  the  central  nervous  system  which  has 
to  group  together  all  the  muscles  > which  must  work  for  a 
common  end,  and  to  give  to  each  the  amount  of  action 
which  is  necessary. 

Let  us  suppose  that  a  certain  number  of  men  are  em- 
ployed in  moving  heavy  burthens.  If  these  men,  although 
very  strong,  are  ill  directed,  if  their  movements  are  not 
harmonious,  and  their  forces  are  not  exerted  together, 
ten  of  them  will  not  do  as  much  work  as  five  would  do 
if  well  directed  and  accustomed  to  work  together. 

Similarly,  an  athlete  who  has  well-trained  muscles  at 


202  PHYSIOLOGY  OF  BODILY  EXERCISE. 

his  disposal,  that  is  to  say,  muscles  used  to  work  together, 
will  do  more  work  than  a  stronger  man  who  does  not 
know  how  to  use  his  limbs. 

The  work  which  a  man  can  perform  does  not  only 
depend  on  the  real  strength  of  his  muscles,  but  also  on 
his  knowledge  of  the  way  in  which  to  use  them. 

Muscular  education  leads  to  an  economy  of  force. 
Every  muscular  contraction  in  a  well-trained  man  has  a 
direct  and  useful  effect  on  the  desired  movement  :  in  an 
unpractised  man  the  action  of  many  muscles  is  paralysed 
by  the  awkward  intervention  of  their  antagonists.  It  is 
only  after  unconscious  and  often  repeated  trials  that  the 
will  knows  to  which  muscle  it  must  apply  for  the  per- 
formance of  the  desired  movement.  Every  movement 
becomes  more  perfect  through  an  apprenticeship,  because 
the  performance  is  in  the  end  entrusted  to  the  muscles 
most  fitted  for  the  purpose. 

We  should  be  tempted  to  believe  that  every  muscle  has 
a  purpose  fixed  in  advance,  and  that  it  is  enough  to  wish 
to  displace  a  portion  of  the  body  in  a  given  direction  to 
immediately  know  to  which  muscular  group  the  per- 
formance of  the  movement  should  be  entrusted.  In 
general  it  is  easy-for  a  man,  or  even  an  ape,  to  imitate 
very  faithfully  a  movement  or  an  attitude  shown  to  him, 
for,  as  a  rule,  these  are  muscular  actions  which  the  indi- 
vidual has  already  performed  often  enough.  But  this  is 
not  the  case  as  regards  new  actions  to  which  the  body  is 
not  accustomed,  and  assiduous  practice  is  needed  to 
learn  certain  movements  not  already  known,  or  even 
to  improve  movements  already  known. 

There  is  only  one  useful  way  of  studying  move- 
ments :  to  perform  them.  In  doing  them  ourselves,  we 
easily  understand  how  for  each  action,  even  the  most 
insignificant,  there  are  several  methods  of  which  the 
(lifierence  usually  escape  the  spectator,  but  which  are 
felt  by  the  performer.  By  an  apprenticeship  we  learn 
to  make  a  choice  among  these  different  methods,  and 
to  take,  naturally,  that  which  represents  the  greatest 
economy  of  force  for  the  work  done. 

Hence  the  great  difficulty  of  estimating  the  strength 


MODIFICATION   OF  FUNCTIONS  BY  WORK.        203 

of  an  individual  by  measuring  his  effort.  We  may 
assert  that  no  kind  of  dynamometer  can  give  an  exact 
measure  of  the  strength  of  a  man,  for  each  has  his  own 
way  of  striking,  drawing,  or  pressing  the  dynamometer. 

What  exercise  is  there  which  at  first  sight  appears  to 
be  more  entirely  dependent  on  brute  force,  to  be  less  sub- 
ject to  muscular  education,  to  be  more  independent  of  the 
dexterity  of  the  individual,  than  the  act  of  striking  an 
anvil  with  a  heavy  hammer?  But  the  force  of  the  blow 
does  not  only  depend  on  the  strength  of  the  smith. 
Everyone  must  have  seen  at  fairs  a  kind  of  dynamo- 
metric  apparatus,  consisting  of  an  upright  post  with  a 
horizontal  platform  at  its  base.  The  man  who  wishes  to 
try  his  strength  strikes  this  platform  with  a  long-handled 
hammer.  By  a  simple  mechanism,  the  blow  of  the  ham- 
mer is  communicated  to  a  doll,  which  rises  along  the 
post.  The  height  to  which  the  doll  rises  measures  the 
force  of  the  blow.  Now,  usually,  the  most  vigorous  men 
do  not  drive  the  doll  as  high  as  the  proprietor  of  the 
machine,  though  he  may  be  a  man  of  quite  ordinary 
strength,  for  he  hashad  leisure  to  practice  with  his  machine, 
and  knows  best  how  to  use  it.  There  is  method  in  strik- 
ing a  blow  with  a  hammer  ;  those  who  have  not  the  trick 
of  the  thing  hold  back  their  blow^,  that  is,  they  throw  into 
action  muscles  which  are  opposed  to  the  movement.  By 
the  antagonistic  action  of  these  muscles  the  force  of  the 
blow  is  lessened,  and  although  there  is  greater  expendi- 
ture of  muscular  strength,  since  a  greater  number  of 
muscles  are  in  action,  the  apparent  result  is  less. 

There  is  method  in  walking,  method  in  running, 
method  in  raising  a  burthen  Vv'ith  as  little  effort  as 
possible.  The  practice  of  an  exercise  leads  then  to  a 
diminution  of  muscular  expenditure,  to  an  economy  of 
work,  whence  results  an  apparent  increase  of  the  strength 
of  the  man  who  does  the  work. 

The  influence  of  education  is  not  only  exercised  on 
muscular  movements  :  all  the  great  functions  are  modi- 
fied by  practice  in  order  to  adapt  them  to  the  needs  of 
an  action  performed  every  day.  If  the  pianist  learns  to 
move  his  fingers  with  precision  and  rapidity,  the  singer 


204  PHYSIOLOGY  OF   BODILY   EXERCISE. 

learns  to  breathe  deeply  and  to  regulate  his  breathing,  so  as 
not  to  interfere  with  the  song  by  an  ill-timed  inspiration. 

In  violent  exercises  the  education  of  the  breathing 
has  a  capital  importance.  Experienced  runners  gain 
control  over  the  reflex  respiratory  movements,  and  make 
very  deep  respirations,  Avhile  novices,  obeying  blindly 
the  needs  of  their  inexperienced  lungs,  get  out  of  breath 
through  too  precipitate  and  shallow  movements  of  the 
thorax.  It  is  possible  to  regulate  the  breathing  according 
to  certain  methodically  enunciated  principles,  but  a  man 
attains  this  regulation  just  as  surely,  if  not  as  quickly, 
by  the  more  or  less  conscious  feeling  his  way  which  is 
necessary  in  every  new  exercise. 

By  da'ily  resisting  a  reflex  movement  at  first  irre- 
sistible, it  is  not  impossible  to  learn  to  control  it.  People 
who  restrain  tears  or  laughter,  who  check  a  sneeze,  of 
stop  a  fit  of  coughing,  prove  that  an  energetically 
directed  effort  of  will  can  strive  effectively  against  an 
instinctive  impulse  and  an  organic  need. 

On  the  other  hand  it  is  possible,  by  surrendering  to 
spontaneous  movements,  to  create  real  illnesses.  Certain 
patients,  coughing  habitually  to  excess,  suffer  in  the  end 
from  constant  paroxysms  of  nervous  coughing^  which  no 
remedies  cure,  unless  there  be  added  to  them  a  strong 
effort  of  the  will. 

The  education  of  reflexes,  the  subjecting  of  move- 
ments which  are  ordinarily  spontaneous  to  the  control 
of  the  will,  may  then  lead  to  great  diminution  of  fatigue 
in  the  performance  of  bodily  exercise. 

II. 

The  purely  functional  changes  which  occur  in  the 
system  through  practice  can  only  be  attributed  to  the 
regulating  agent  of  the  organic  functions,  that  is  to  say 
to  the  nervous  system. 

It  is  the  nervous  system  which  presides  over  all  the 
functions  and  controls  the  activity  of  all  the  organs.  If 
there  is  any  disturbance  in  the  structure,  the  nutrition, 
or  simply  in  the  working  of  the  nervous  system,  various 
disturbances  in  the  organic  functions  immediately  ensue, 
notwithstanding  the  perfect  integrity  of  the  apparatus 


MODIFICATION    OF   FUNCTIONS    BY   WORK.         20$ 

by  which  they  are  carried  on.  In  the  muscles  we  sec 
paralyses,  contractures  or  convulsions  follow  the  slightest 
injuries  of  the  brain,  the  spinal  cord,  or  the  nerves.  In 
the  internal  organs  also  we  see  serious  disturbances  in 
the  frequency,  the  rhythm,  or  the  intensity  of  the  move- 
ments of  the  heart  and  lungs,  in  the  absence  of  all  injury 
to  the  apparatus  of  respiration  and  circulation,  under  the 
simple  influence  of  a  transient  disturbance  of  the  circu- 
lation in  certain  parts  of  the  nerve  centres.  Finally  the 
glands  may  present  a  complete  perversion  of  their  secre- 
tions under  the  influence  of  the  slightest  lesions  of  the 
nerves  by  which  they  are  supplied. 

We  can  only  attribute  to  the  nervous  system,  and  to 
changes  in  its  elements,  the  improvements  observed  in 
the  working  of  the  organs  when  these  organs  show^  no 
changes  of  structure  capable  of  explaining  them. — If  a 
muscle  after  reaching  the  maximum  development  of  which 
it  is  capable,  continues  to  increase  in  power  through 
practice,  although  it  does  not  increase  in  size,  we  can  only 
explain  this  purely  dynamic  increase  in  strength  by 
changes — known  or  unknown — in  that  part  of  the  nervous 
system  which  has  to  do  with  its  contraction. 

Now  in  studying  the  structure  of  the  nerves  in  a  man 
accustomed  to  w^ork,  we  can  point  to  no  appreciable 
change,  any  more  than  w^e  can  in  the  spinal  cord  or  the 
brain.  Between  the  nervous  substance  of  a  man  given  to 
physical  exercise,  and  that  of  a  man  habitually  inactive 
it  is  impossible  to  recognise  any  differential  characters 
corresponding  to  the  w^ell  defined  differences  between 
the  fibre  of  a  muscle  often  at  work,  and  of  a  muscle 
usually  inactive.  But  we  must  admit  that  the  law  of 
the  transformation  of  the  organs  by  practice  cannot 
affect  all  the  organic  apparatus  of  the  body  to  the  ex- 
clusion of  one  only.  It  has  been  proved  that  the  grey 
fnatter  of  the  brain  is  indispensable  to  the  performance 
of  voluntary  movements  :  how  can  we  believe  that  its 
nutrition  is  uninfluenced,  and  that  no  trace  is  left  by 
this  repeated  activity,  when  we  see  that  all  the  organs 
which  are  even  indirectlv  associated  in  work,  the  luncfs 
and  the  skin  for  instance,  ]\ave  an  external  conformation 
15 


205  PHYSIOLOGY  OF  BODILY  EXERCISE. 

and  an  intimate  structure  which  betray  to  the  experienced 
eye  the  habits  of  work  of  the  possessor. 

If  it  lias  been  demonstrated  that  "  function  makes 
structure,"  if  work  changes  the  apparatus  by  the  aid  of 
which  it  is  performed,  muscular  exercise  must  neces- 
sarily produce  changes  in  the  brain,  an  instrument  indis- 
pensable in  the  performance  of  voluntary  movement.  The 
nervous  working  which  goes  on  in  the  grey  matter  of  the 
brain  for  the  purpose  of  throwing  a  muscle  into  action,  must 
influence  the  nutrition  of  this  portion  of  the  brain  just  as 
much  as  contraction  influences  the  nutrition  of  muscle. 

The  changes  in  the  motor  cerebral  cell,  under  the 
influence  of  muscular  work,  have  not  yet  been  apparent 
to  the  eye,  and  observation  has  not  hitherto  given  direct 
confirmation  of  these  ideas  which  seem  so  legitimate  on 
analogical  grounds.  But  one  observation  has  at  least 
been  recorded  which  may  serve  as  an  indirect  proof  ot 
this  hypothesis.  This  is  the  observation  recorded  by 
Dr.  Luys  in  his  work  on  The  Brain,  proving  that  after 
loss  of  the  function  of  a  limb  certain  parts  of  the  grey 
matter  of  the  brain  undergo  atrophy,  due  to  defective 
action  of  the  motor  cells.  If  defective  action  can  cause 
atrophy  of  the  cells  which  preside  over  certain  move- 
ments, we  cannot  refuse  to  admit  that  their  frequent 
activity  should  promote  their  increased  development. 

It  is  then  probable  that  certain  portions  of  the  brain 
which  preside  over  voluntary  movement  are  developed 
by  muscular  exercise,  just  as  certain  other  parts  of  this 
organ,  concerned  in  intellectual  operations,  may  be 
developed  by  mental  work.  Certain  portions  of  the 
nervous  system  form  a  part  of  the  organs  of  movement, 
and  we  cannot  believe  that  the  law  ^^ function  makes 
structure  "  should  not  be  as  true  for  the  nervous  elements 
as  for  the  other  elements  associated  in  work. 

The  material  changes  undergone  by  the  brain  as  a 
consequence  of  work,  extend  in  all  probability  to  the 
spinal  cord  and  the  motor  nerves. 

The  motor  nerve  conducts  to  a  muscle  the  order  of 
the  will,  but  we  have  seen  *  that  the  stinmli  which  f  ass 

*  Part  I.     Chapter  I. 


MODIFICATION   OF   FUNCTIONS   BY  WORK.        20/ 

along  the  nerve-filament  are  strengthened  in  transit  in 
the  manner  shown  by  Pfluger  in  formulating  his 
avalanche  theory.  A  nerve  is  a  reinforcing  apparatus 
as  well  as  a  conducting  organ.  We  may  well  believe 
that  a  still  unknown  molecular  change  increases  its 
amplifying  power  and  thus  allows  a  more  moderate 
voluntary  effort  to  produce  a  stronger  muscular  con- 
traction. In  any  case  the  man  accustomed  to  use  his 
muscles  seems  to  obtain  from  them  without  effort  a 
much  more  considerable  amount  of  work,  and  this 
without  an  increase  in  the  muscular  fibres  sufficient  to 
account  for  the  greater  ease  with  which  they  contract. 
The  nerve  seems  to  transform  a  moderate  stimulus 
which  passes  along  it,  into  an  energetic  one,  and  a  man 
accustomed  to  work  performs,  zvithoict  effort  of  zuill, 
movements  which  would  formerly  have  caused  him 
excessive  voluntary  strain. 

As  for  the  spinal  cord,  it  acquires  by  work,  powers 
which  cannot  be  understood  unless  we  suppose  there  is 
concomitant  organic  change  :  it  remembers  often 
repeated  movements,  and  we  may  see,  in  an  animal 
deprived  of  its  brain,  the  automatic  performance  of 
complicated  muscular  actions,  such  as  walking,  without 
the  intervention  of  conscious  will. 

The  power  of  automatism  acquired  by  daily  practice 
comes  to  our  aid  constantly  in  the  performance  of 
difficult  and  rapid  movements.  In  fencing  for  instance, 
many  actions  often  performed  have  become  automatic, 
and  are  performed  so  quickly  that  there  could  not  be 
time  for  the  successive  co-ordination  of  all  the  move- 
ments. How^  can  the  spinal  cord  have  the  power  of  re- 
producing automatically  without  the  conscious  help  of  the 
brain,  a  very  complicated  movement,  if  the  repeated  per- 
formance of  this  movement  had  not  impressed  on  the 
nervous  tissues  which  call  it  forth,  persistent 
modifications  ? 

Does  it  seem  strange  to  speak  of  a  movement  leaving 
a  material  imprint  on  the  nervous  tissue  ?  But  would  it 
not  have  seemed  strange,  twenty  years  ago,  to  hear  it 
said  that  a  word  spoken  aloud  should  leave  on  a  metallic 


20o  PHYSIOLOGY  OF   BODILY  EXERCISE. 

plate  an   imprint  capable  of  reproducing  it?     But  the 
phonograph  has  shown  that  this  was  no  chimœra. 

Thus  it  is  difficult  to  prove  by  direct  arguments  that 
the  nervous  system  participates  in  the  organic  changes 
produced  in  the  human  body  by  the  influence  of  work. 
It  will  doubtless  be  still  more  difficult  to  demonstrate 
scientifically  that  the  psychical  faculties  are  influenced  by 
muscular  exercise,  and  are  modified,  by  the  very  fact  of 
work,  in  a  sense  favourable  to  the  performance  of  an 
exercise  which  is  daily  practised.  Still  it  is  incontest- 
able that  certain  faculties  of  the  soul  come  into  play  in 
bodily  exercise  to  excite  the  contraction  of  muscles  and 
to  co-ordinate  movements  ;  it  is  also  incontestable  that 
these  faculties  are  improved  and  developed  by  exercise. 

The  faculties  which  preside  over  the  co-ordination  of 
movements  are  developed  by  the  performance  of  difficult 
exercises,  and  their  improvement  endows  a  man  with  the 
quality  we  call  skill. 

The  faculty  which  orders  a  muscle  to  act  and  which 
gives  it  the  stimulus  necessary  for  its  contraction,  is 
called  the  Will  :  it  also  is  developed  and  improved  by 
the  repeated  use  made  of  it.  It  shows  its  acquired 
superiority,  in  the  sphere  of  movement,  by  a  greater 
persistence  of  effort,  by  a  greater  tenacity  in  muscular 
action.  The  person  who,  every  day,  in  spite  of  the 
different  pains  of  fatigue,  sustains  energetic  and  pro- 
longed muscular  efforts,  acquires  a  greater  power  of 
Willing^  and  from  this  acquisition  result  certain  very 
striking  changes  in  his  moral  disposition.  The  habitua- 
tion to  work  gives  to  a  man  greater  energy  of  will 
considered  as  a  motor  force,  and  from  this  change  of  a 
moral  order,  as  much  as  from  that  of  a  material  order, 
results  a  particular  form  of  courage  which  we  may  call 
Physical  Courage. 

Physical  courage  is  manifestly  increased  by  the 
practice  of  muscular  exercises.  It  is  almost  exclusively 
in  men  whose  daily  work  is  laborious,  or  who  are  given 
to  violent  exercises,  that  we  see  bold  and  energetic 
actions.     If  we  see  in   the  street  a  passer-by  seize  the 


MODIFICATION   OF   FUNCTIONS   BY  WORK.        209 

head  of  a  runaway  horse  or  try  to  stop  a  dangerous 
malefactor,  we  may  at  once  be  almost  sure  that  the  man 
is  a  labourer  used  to  hard  work,  or  a  sportsman  fond  of 
physical  exercises.  The  practice  of  muscular  work  and 
the  habituation  to  bodily  exercise  dispose  a  man  to 
brave  all  forms  of  material  danger. 

The  most  remarkable  proof  of  the  development  of 
physical  courage  by  the  habituation  to  work  is  furnished 
by  the  spectacle  frequent  enough  in  England,  of  a  prize- 
fight. The  preparation  of  prize-fighters  is,  of  all  forms 
of  training,  that  which  demands  the  most  complete 
habituation  of  the  body  to  all  kinds  of  muscular  activity 
pushed  to  extreme  limits.  But  at  the  same  time  that  he 
acquires  the  power  of  resisting  fatigue,  and  increase  of 
strength,  the  ordinary  results  of  habituation  to  work, 
the  prize-fighter  gains  also  an  energy  of  will,  a  tenacity 
in  ficrhtino-  which  is  almost  bevond  belief. 

"  In  a  celebrated  fight  between  ]\Iaffey  and  ]\Iacarthy, 
which  lasted  four  hours  forty-five  minutes,  one  of  them 
was  knocked  down  one  hundred  and  ninety-six  times 
before  allowing  that  he  was  beaten."  *  In  another  fight 
one  of  the  champions  received  in  the  first  round  a  blow 
which  broke  his  left  arm.  He  put  the  fractured  limb  in 
a  sling  and  went  on  fighting  for  an  hour  and  a  quarter, 
till  a  blow,  which  made  him  lose  consciousness  for  some 
minutes,  compelled  him  to  allow  that  he  was  beaten. 

This  incredible  strength  of  will,  which  enables  the 
prize-fighter  to  remain  firm  before  such  terrible  blows,  is 
not  derived  from  anger.  It  is  an  axiom  in  prize-fighting 
that  "  a  boxer  who  no  longer  smiles  is  a  boxer  beaten."  t 
When  the  open  mouth  of  anger  replaces  the  smile  on  the 
lips  of  one  of  the  champions,  betters  abandon  him  and  his 
opponent  becomes  the  favourite.  It  is  only  training, 
that  is,  habituation  to  violent  and  prolonged  muscular, 
exercise,  which  gives  such  a  surprising  energy  to  these 
men,  wiiom  Royer-Collard  declared  to  be  "so  different 
from  other  men." 

*  Royer-Collard.     loc.  cit. 

+  Leboucher.     Manuel  de  Boxe. 


CHAPTER  ÎY. 

TRAINING. 

Various  meanings  of  the  word  TVaz/z/zzcr—Xraining-,  as  we  under- 
stand it  here,  is  the  Adaptation  of  the  Organism  to  Work- 
Natural  Training  and  Methodical  Training.  Methods  of 
Training  ;  rarely  put  in  force  in  France  ;  very  widely  Practised 
in  England— Training  of  Boxers— Training  of  Oarsaien.  A 
SDecimen  of  Method— Physiological  explanation  of  the  Pheno- 
mena—The Loss  of  Weight  ;  Diet  ;  Care  of  the  Skin— Capital 
Importance  of  Muscular  Work  in  Training— Temperament  of 
the  Trained  Man.  Advantages  and  Disadvantages  of  his 
Condition, 

Î. 

We  call  U'aining  a  series  of  practices  the  object  of  which 
is  to  render  a  man  or  an  animal,  as  completely  and 
quickly  as  possible,  fit  for  the  performance  of  a  given 
work. 

The  word  training  is  often  used  in  a  wider  sense.  It  is 
used  as  synonymous  with  "  preparation,"  and  is  applied 
to  methods  in  which  muscular  work  plays  no  part. 
Thus  divers  are  trained  in  order  that  they  may  be  able 
to  hold  their  breath  longer  ;  jockeys  are  trained  to  make 
them  lighter,  and  to  facilitate  the  work  of  the  horse 
which  carries  them  ;  the  word  is  even  used  in  an  in- 
tellectual sense,  and  we  say  that  cerebral  training  im- 
proves a  man's  understanding. 

In  reality  all  the  varieties  of  training  may  be  reduced 
to  one  :  adaptation  of  the  organism  to  certain  particular 
conditions  of  activity.  To  be  trained  implies  that  the 
organs  have  undergone  modification  ;  we  may  believe 
that  the  brain  of  a  man  of  science  differs  from  that 
of  a  porter  ;  we  are  certain  that  the  conformation  of  a 


TRAINING.  211 

prlze-fi^litcr  in  perfect  condition  is  not  the  same  as  that 
of  a  student. 

But  we  must  say  that  the  chanj^cs  in  the  structure  of 
the  organs  produced  by  training  are  not  very  profound  : 
they  are  quickly  produced  and  quickly  disappear. 

A  man  in  training  has  for  the  time  a  particular 
temperament.  He  has  acquired  a  new  conformation 
which  gives  him  special  aptitudes,  but  in  nature  he  is 
unchanged  ;  if  he  returns  to  the  mode  of  life  he 
relinquished  when  he  began  training,  he  at  once  loses 
all  the  powers  he  had  gained.  To  keep  himself  in  the 
trained  state,  or,  as  trainers  say,  in  condition^  he  must 
continue  the  practices  which  have  brought  about  the 
perfect  conformation  of  his  organs  and  the  easy 
performance  of  their  functions. 

From  the  point  of  view  of  muscular  exercise,  the 
condition  of  training  inevitably  results  from  the  habitu- 
ation to  work.  All  professions  which  demand  a  great 
expenditure  of  muscular  strength  maintain  the  persons 
who  practise  them  in  perfect  condition  ;  they  make  them 
as  strong  and  as  resisting  as  their  constitution  permits. 

A  very  active  and  laborious  life  is  then  enough  to 
bring  about  in  the  end  fitness  for  work  and  power  of 
resisting  fatigue,  without  it  being  necessary  to  observe 
the  hygienic  and  dietetic  practices  recommended  by 
trainers.  Wolves  have  no  need  to  abstain  from  certain 
articles  of  food,  or  to  limit  the  amount  of  water  they 
drink,  in  order  to  make  their  muscles  as  hard  as  iron 
and  to  have  lungs  to  which  breathlessness  is  unknown. 

But  we  must  recognise  that  the  benefits  derived  from 
work  are  gained  with  astonishing  rapidity  when  the 
athlete  submits  to  a  certain  regulation  of  his  diet,  and  to 
certain  accessory  hygienic  performances  which  make  up 
a  method  much  in  vogue  in  certain  countries,  under  the 
name  of  training. 

This  method  is  not  yet  common  in  France.  In  this 
country  the  mass  of  the  public  only  knows  of  training 
as  it  applies  to  race-horses  and  jockeys,  who  are 
regarded  as  emaciated  beings  who  are  made  to  fast  to 
an  extreme  degree  in  order  to  reduce  their  weight. 


212  PHYSIOLOGY  OF   BODILY-  EXERCISE. 

This  loss  of  weight  is  however  only  apparent  in  race- 
horses, and  generally  these  animals,  angular  and  thin, 
weigh  at  least  as  much  as,  and  sometimes  more,  than  they 
did  when  training  began.  Only  the  nature  of  their  tissues 
is  no  longer  the  same  ;  their  diet  has  caused  the 
disappearance  of  all  the  materials  useless  to  movement, 
and  developed  on  the  other  hand  the  tissues  necessary 
for  work.  Their  fat  has  almost  entirely  disappeared  and 
been  replaced  by  muscle. 

The  training  of  jockeys  effects  only  half  of  this.  In 
them  the  fatty  tissues  disappear,  but  the  muscular  tissues 
do  not  increase  ;  in  this  manner  the  loss  is  not  compen- 
sated by  receipts,  and  the  mass  of  the  body  diminishes. 
In  the  jockey  there  is  no  desire  for  an  increase  in 
muscular  strength,  only  for  diminution  in  weight,  for  the 
object  is  to  put  as  light  a  man  as  possible  on  the  back  of 
the  horse. 

The  training  of  jockeys  will  not  serve  as  a  typQ  in 
this  study  ;  it  is  an  abuse  of  language  to  call  a  man 
trained  who  is  made  to  become  as  thin  as  possible  without 
trying  to  develop  in  him  any  special  energy.  Training, 
as  we  understand  it,  supposes  the  acquisition  of  certain 
active  qualities,  of  a  certain  superiority  in  the  perform- 
ance of  the  special  movements  of  an  exercise.  As 
regards  the  jockey,  we  will  rather  apply  the  word 
training  to  the  period  of  time  in  which  he  is  learning  to 
ride.  The  man  entrusted  with  the  breaking  in  of  a 
young  thorough-bred  colt,  undergoes  training  in  the 
fullest  sense  of  the  word,  for  the  struggles  of  his  pupil 
make  him  bring  vigorously  into  action  all  the  muscles 
necessary  for  keeping  a  horseman  in  the  saddle,  and 
these  muscles  are  very  numerous. 

In  France  the  racing  stables  have  trainers  for  their 
horses.  In  England  men  also  have  trainers  who  pre- 
pare themi  for  walking,  rowing,  or  boxing  contests.  The 
betting  mania  is  the  origin  and  the  motive  power  of  all 
these  methods  intended  to  give  a  champion  every 
possible  chance  ;  but  an  unheard-of  resistance  to  fatigue, 
an  incredible  vigour,  and  perfect  health,  are  the  consé- 
quences of  them. 


TRAINING.  213 

Here  are  the  facts  exposed  by  Royer-Collard  in  1842 
before  the  Academy  of  Medicine,  concerning  the  results 
of  systematic  training,  which  produces  this  model  of  a 
man  who  has  gained  the  acme  of  development  of 
strength,  and  power  of  resistance,  and  who  is  called  a 
prize-fighter. 

"  The  man  who  has  been  trained  has  not  sensibly  lost 
weight,  unless  he  was  very  fat  before  he  got  into 
condition.  Usually,  indeed,  he  weighs  a  few  pounds 
more,  but  his  limbs  have  singularly  increased  in  size. 
His  muscles  are  hard,  prominent,  and  feel  very  elastic  ; 
they  contract  with  extraordinary  force  under  the 
influence  of  an  electric  shock.  The  abdomen  is  re- 
tracted, the  chest  expanded  ;  breathing  full  and  deep, 
capable  of  long  efforts.  The  skin  is  firm,  sleek,  free 
from  all  eruption.  We  notice  that  the  skin  over  the 
axillary  regions  and  the  sides  of  the  chest  does  not 
tremble  during  the  movements  of  the  arms  ;  it  seems  to 
be  perfectly  adherent  to  the  subjacent  muscles.  This 
firmness  of  the  skin  and  density  of  the  cellular  tissue, 
resulting  from  the  absorption  of  liquids  and  of  fat, 
oppose  the  formation  of  effusions.  (Comptes  rendus 
Acad,  de  Medicine?) 

Let  us  see  what  the  author  says  about  the  powers 
in  fight  of  these  men  whom  we  have  just  described  : 

"  Prize-fighters  are  naked  to  the  waist,  and  try  to 
strike  their  adversary  with  all  possible  force  anywhere 
between  the  head  and  the  umbilicus.  If  one  of  them  is 
knocked  down,  dizzy  from  a  violent  blow,  he  is  allowed 
a  minute's  rest.  Before  the  whole  minute  has  passed  he 
gets  up  and  goes  on  fighting,  or  he  is  declared  beaten.» 
Ordinary  fighters,  in  a  fight  of  an  hour  and  a  half,  stop 
in  this  way  thirty  or  forty  times. 

"  The  combat  may  last  for  from  some  minutes  to  four 
or  five  hours.  We  may  imagine  that  serious  injuries, 
and  even  death,  may  be  the  issue.  Sad  instances  of  this 
have  occurred,  but  they  are  extremely  rare.  Usually  a 
few  days  afterv/ards  there  are  no  traces  of  these  terrible 
blows, 

"  A  prodigious  strength,  a  singular  skill,  and  incredible 


214  PHYSIOLOGY  OF   BODILY  EXERCISE. 

insensibility  to  blows,  and  at  the  same  time  perfect 
health,  such  are  the  phenomena  presented  by  these  men, 
so  very  different  from  other  men." 

To  bring  a  man  to  this  degree  of  vigour  and  resistance 
to  fatigue,  six  weeks  are  sufficient.  During  this  shoit 
period  the  man  performs  a  gradually  increasing  quantity 
of  muscular  work  ;  but  he  must  also  confine  himself  to 
a  particular  diet,  and  follow  certain  special  hygienic 
practices. 

All    methods    of  training   have    a   double    object: — 

1.  To    develop    the    muscular   energy  of    the   subject  ; 

2.  To  increase  his  power  of  resisting  fatigue.  These 
two  objects  are  attained  by  means  empirically  ascer- 
tained, the  excellent  effect  of  which  has  been  shown  by 
experience,  without,  hitherto,  a  satisfactory  explanation 
having  been  given.  To  get  an  idea  of  the  usual  pro- 
cesses of  training,  it  will  be  enough  to  .read  the  account 
of  the  training  of  a  certain  J.  G.,  a  butcher,  preparing  for 
a  rowing  match  under  the  direction  of  Symes. 

This  training  much  resembles  that  of  prize-fighters, 
for  its  object  is  to  develop  the  whole  muscular  strength 
of  the  subject,  and  to  increase  to  the  highest  possible 
degree  his  power  of  resisting  fatigue.  It  differs  however 
in  one  important  detail  ;  the  weight  of  the  oarsman  must 
be  diminished  as  much  as  possible  in  order  to  lessen  the 
weight  he  has  to  pull.  So  it  will  be  noticed  that  the 
subject  of  the  following  remarks  lost  37  pounds  in  weight, 
while  the  prize-fighters  are  of  the  same  weight  at  the 
end  of  training  as  when  they  began  the  course.  We 
borrow  the  following  observation  from  Dr.  Worthington's 
work  on  "  Obesity." 

We  give  the  regimen  followed,  and  its  results  : — 
^^  April  1st,     To  get  up  at  6  a.m.,  take  40  grammes  of 
sulphate  of  magnesia,  and  walk  gently  for  half-an-hour. 

8  a.m.  breakfast,  composed  of  mutton  chop  or  beef 
steak,  watercress,  half  a  pint  of  tea  with  a  little  milk 
and  sugar,  a  small  quantity  of  dry  bread  or  toast. 

9  a.m.  to  noon,  to  walk  at  the  rate  of  three  miles  an 
hour. 


TnAlNING.  215 

1  p.m.  dinner,  composed  of  (lean)  roast  beef  or  mutton 
under-done,  or  well-done,  according  to  taste,  green  vege- 
tables, three  quarters  of  a  pint  of  old  ale,  a  small 
quantity  of  stale  bread. 

2  p.m.  to  4  p.m.  to  walk  at  the  rate  of  three  miles  an 
hour. 

5  p.m.  half  a  pint  of  tea,  dry  bread  or  toast,  two  raw 
eggs,  beaten  up  in  the  tea,  or  else  two  soft-boiled  eggs. 

6  p.m.  to  8  p.m.  to  walk  at  the  rate  of  three  miles  an 
hour. 

9  p.m.  supper,  half  a  pint  of  old  ale  with  a  piece  of 
dry  bread  ;   to  walk  gently  for  half  an  hour. 

10  p.m.  to  go  to  bed. 

Same  regimen  for  three  days. 

April 4th.  To  get  up  at  6  a.m.  ;  to  walk  gently  for 
half  an  hour. 

8  a.m.  breakfast  as  before. 

10  a.m.  to  dress  in  several  complete  suits  of  flannel 
for  loss  of  weight  (wasting)  ;  to  zvalk  for  two  hours 
as  quickly  as  possible,  and  to  take  a  sliower-bath  imme- 
diately on  returning,  perspiration  being  at  its  maximum. 
A  small  glass  of  sherry  or  a  gill  of  old  ale,  if  thirst  is 
unbearable. 

1.30  p.m.  dinner  as  before. 

2.30  p.m.  to  4  p.m.  to  walk  at  a  moderate  pace  (three 
miles  an  hour). 

4  p.m.  to  row  two  miles. 

5.30  tea  as  before. 

April  s^li-  Result  of  the  course  of  wasting  :  a  loss  of 
weight  of  ^  lbs. 

Exercise  before  breakfast,  breakfast  as  before. 

1 1.30  a.m.  to  row  two  miles,  followed  by  a  cold  shower- 
bath. 

12.30  p.m.  a  glass  of  sherry,  or  a  gill  of  old  ale. 

1.30  p.m.  dinner  as  before. 

2.30  p.m.  to  4  p.m.  to  walk  quickly. 

4  p.m.  to  row  one  mile  as  quickly  as  possible, 

5.30  p.m.  tea. 

9  p.m.  supper. 

10  p.m.  to  go  to  bed. 


2l6  PHYSIOLOGY  OF   BODILY   EXERCISE. 

April 6th.  Same  regimen  :  to  row  two  miles  twice  a 
day,  followed  each  time  by  a  cold  shower-bath.  To 
proceed  thus  till  April  14th. 

April   \/\tJi.     Loss  of  zveight  through  exercise-,  y  lbs. 

Second  wasting  :  same  regimen  in  all  respects  as  on 
April  4th. 

April  i^th.  Result  of  second  wasting;  a  loss  of 
weight  of  4  lbs. 

To  continue  the  ordinary  regimen,  that  is  to  say, 
without  the  wasting,  till  April  23rd  ;  loss  of  weight 
through  exercise,  7  lbs. 

April  2jih.     Third  wasting  :   loss  of  weight  3  lbs. 

Till  May  7th,  ordinary  regimen  of  training  :  loss  of 
weight  through  exercise,  5  lbs. 

May  %tJi.     Fourth  wasting  :  loss  of  weight,  3  lbs. 

Till  May  i^th,  the  day  of  the  race,  ordinary  regimen 
of  training  ;  no  loss  of  weight." 

The  training  had  lasted  six  weeks  and  had  caused  a 
loss  of  weight  of  37  lbs.  It  is  curious  to  note  how  little 
persistent  was  this  result  so  rapidly  attained. 

^^  June  i^th — one  month  later — the  same  individual 
wished  to  be  trained  for  a  rowing  match  of  two  miles. 
Having  returned  to  his  ordinary  habits  he  had  gained  21 
lbs.  in  weight.  As  he  was  much  pressed  for  time  his 
training  only  lasted  eight  days. 

This  short  space  of  timic  was,  however,  sufficient  to 
disembarrass  him  of  his  21  lbs.,  and  put  him  in  condition 
easily  to  win  the  race." 

This  observation  shows  us  how  little  stability  there 
is  in  the  changes  produced  by  training.  We  see  that 
the  athlete  had  returned  in  a  month,  by  resuming  his 
ordinary  habits  of  life,  to  the  conformation  which  violent 
exercise  and  regulation  of  diet,  etc.,  had  so  profoundly 
modified  in  six  weeks. 

If  we  analyse  the  method  of  Symes,  we  notice  there 
are  two  classes  of  practices  :  one  destined  to  increase 
the  volume  of  the  muscles  by  work  ;  the  end  of  the 
others  being  to  diminish  the  mass  of  the  tissues  by 
every  kind  of  outlay. 

We  know  that  the  muscles  increase  in  size  by  the  very 


TRAINING.  217 

fact  of  exercise,  and  we  need  not  insist  on  this  to  explain 
how  muscles  which  have  become  larger,  make  the  per- 
son stronger — but  it  is  necessary  to  explain  the  effect 
of  the  evacuations  in  increasing  the  power  of  resisting 
fatigue. 

We  know  that  any  loss  undergone  by  the  system 
tends  to  increase  the  power  of  absorption  of  the  vessels. 
Profuse  sweatings,  copious  diuresis,  repeated  intestinal 
evacuations,  large  losses  of  blood,  very  greatly  increase 
the  desire  for  the  assimilation  of  liquids.  This  desire 
leads  us  to  produce  a  kind  of  compensation  between  the 
losses  and  gains  of  the  blood.  It  is  usually  satisfied  at 
the  expense  of  liquid  nutriment  from  without,  and  shows 
itself  as  increased  thirst,  but  it  is  also  manifested  by  a 
tendency  to  absorption  of  certain  materials  from  the 
organism  itself  In  this  case  the  process  of  assimilation 
is  known  as  resorption. 

In  therapeutics  we  often  make  use  of  the  force  of 
compensatory  resorption  to  bring  about  the  disappear- 
ance of  morbid  substances  which  have  accumulated  in 
certain  parts  of  the  body.  Thus  liquids  effused  into  the 
natural  cavities  or  infiltrated  through  the  skin  and  the 
muscles,  may  be  removed  by  free  purgation,  or  by  the 
prolonged  use  of  diuretics,  and  even  by  the  influence  of 
repeated  sweatings.  We  then  see  these  patients  freed 
from  the  pathological  liquids  which  were  embarrassing 
them,  and  they  lose  weight. 

The  compensatory  work  of  resorption  is  not  confined 
to  liquids,  but  often  influences  unstable  solid  tissues, 
such  as  fat.  We  see  persons  become  thin  under  the  in- 
fluence of  excessive  perspiration.  It  is  in  virtue  of  a 
compensatory  resorption  that  the  fat  of  a  man  who  is 
training  can  diminish  under  the  influence  of  purgations, 
and  of  the  sweats  produced  by  the  operations  he  goes 
through. 

What  is  the  advantage  of  the  resorption  of  fats  from 
the  point  of  view  of  resisting  fatigue  ?  We  have  already 
discussed  this  at  length  and  it  will  be  sufficient  here  to 
repeat  :  (i)  that  fat  increases  the  useless  weight,  the  dead 
weight  of  a  man  ;  (2)  It  hinders  the  cooling  of  the  body 


2l8  PHYSIOLOGY  OF   BODILY  EXERCISE. 

during  work  ;  (3)  It  increases  by  its  combustion  tbe 
production  of  carbonic  acid.  Increase  of  mechanical 
work,  the  movements  being  the  same  ;  increase  of  the 
disturbances  due  to  excessive  heating  of  the  body  ; 
increase  of  breathlessness  for  the  same  muscular  effort  : 
such  are  the  causes  of  fatigue  due  to  excess  of  the  fatty 
tissues. 

Loss  of  weight  is  then  the  first  stage  of  training.  This 
result  is  obtained  by  the  very  fact  of  work,  owing  to  the 
combustion  of  the  reserve  materials  ;  but  it  is  rendered 
more  rapid  by  a  number  of  accessory  means,  rubbing, 
wrapping  up  in  damp  cloths,  vapour  baths,  very  thick 
clothing,  etc. 

We  may  convince  ourselves  by  experiment  that  the 
disappearance  of  fat  always  leads  to  the  diminution  of 
certain  of  the  discomforts  of  fatigue,  and  above  all  of  the 
heating  of  the  body  and  of  breathlessness.  A  series  of 
hot  air  baths  render  a  man  fit  for  work,  even  before  he 
has  undergone  any  training. 

The  other  practices  of  training  may  be  summed  up  in 
three  precepts  :  (i)  to  avoid  any  article  of  diet  which 
would  tend  to  the  replacement  of  the  lost  fat  :  (2)  to 
favour  the  functions  of  the  skin  :  (3)  to  supply  the  lungs 
with  well-oxygenated  air. 

Watery  beverages  are  forbidden  à  training  man,  since 
they  may,  by  too  quickly  replacing  the  lost  sweat,  dimi- 
nish the  tendency  to  the  resorption  of  fat.  For  a  similar 
reason  they  are  forbidden  farinaceous  food,  sugars,  and 
all  fattening  articles  of  diet,  and  all  substances  said  to 
check  tissue  waste,  such  as  alcohol. 

The  functions  of  the  skin  are  of  great  importance  and 
their  perfect  regularity  is  necessary  from  two  points  of 
view.  In  the  first  place  the  skin  is  an  excretory  organ  : 
it  eliminates  some  of  the  liquid  and  gaseous  waste-pro- 
ducts resulting  from  the  combustions  of  work,  and  we 
have  said  that  the  disorders  of  fatigue  are  chiefly  due  to 
an  intoxication  of  the  blood  by  these  waste-products. 
There  is  then  every  advantage,  from  the  point  of  view  of 
resistance  to  fatigue,  in  favouring  their  prompt  discharge 


TRAINING.  219 

from  the  system.  In  the  second  place  the  skin  is  a  res- 
piratory organ  which  absorbs  oxygen  from  the  air,  aîid 
we  know  how  well-oxygenated  blood  is  vivifying  and 
plastic. 

There  is  another  prescription  to  which  very  great  im- 
portance is  attached  by  trainers  :  this  is  the  tranquillity 
of  a  man's  mind.  The  man  "in  condition  "  is  to  be  kept 
free  from  all  mental  disturbance,  all  depressant  em.otion. 
He  must  avoid  all  nervous  excitement,  and  all  keen 
sensations  ;  he  is  forbidden  sexual  intercourse  as  well  as 
anxieties  and  moral  distress.  We  will  add,  from  our  own 
observations,  that  mental  work  must  also  be  forbidden. 
Mental  work  in  addition  to  exercise  increases  the  ten- 
dency to  dissimilation  of  the  tissues,  and  favours  loss  of 
weight,  but  it  is  opposed  to  the  reconstitution  of  the 
muscular  elements  ;  in  such  a  manner  that  the  person 
given  up  at  once  to  intellectual  fatigues  and  to  muscular 
work  quickly  becomes  thin  and  does  not  replace  by 
muscle,  the  tissues  which  waste.  He  tends  to  fall  into 
the  condition  of  overwork  by  organic  exiiaitstion. 

Finally,  perfect  ventilation  of  the  place  in  which  the 
subject  lives,  is  to  be  considered  a  capital  condition  of 
successful  training.  A  man  who  is  training  must  keep 
away  from  large  towns  and  breathe  air  which  is  vivifying 
and  able  to  make  his  blood  richer  in  oxygen. 

But,  amongst  all  the  agents  which  modify  the  organism 
and  are  employed  by  trainers,  the  most  important  is 
work.  It  may  take  the  place  of  all  the  others,  and  can 
be  replaced  by  none.  Work  alone  is  in  fact  able  to  pro- 
duce the  double  result  which  is  sought,  increased  size  of 
muscles,  and  diminution  of  reserve  materials.  It  directly 
burns  the  fats  by  using  them  to  feed  the  muscular  con- 
traction ;  it  also  uses  them  up  indirectly  by  raising  the 
temperature  of  the  blood,  and  by  warming  the  body  just 
as  would  a  stove,  or  thick  clothing.  Under  the  influence 
of  work  the  combustions  of  the  tissues  are  miore  intense, 
and  a  more  copious  perspiration  brings  about  the  loss 
of  weight  desired  by  the  trainer. 


220  PHYSIOLOGY  OF   EODILY   EXERCISE. 

Besides  these  effects  which  are  common  to  muscular 
work  and  to  the  accessory  means  made  use  of  in  training, 
there  are  results  which  muscular  work  alone  can  give. 
Firstly,  often  repeated  muscular  contraction  is  the  only 
way  of  developing  the  muscles,  and  consequently  in- 
creasing the  strength.  There  is  further  a  form  of  fatigue 
which  cannot  be  diminished,  like  breathlessness,  by  tlie 
resorption  of  fatty  tissues,  that  is  stiffness.  We  know  in 
fact  that  this  form  of  fatigue  is  not  due  to  products 
resulting  from  the  combustion  of  fats,  but  to  products 
resulting  from  the  dissimilation  of  certain  nitrogenous 
materials,  which  are  stored  up  in  the  fibres  of  an  inactive 
muscle. 

Now  work  seems  to  dispose  of  these  nitrogenous 
reserves.  The  sweatings  and  artificial  wastings  which 
much  diminish  the  tendency  to  breathlessness,  do  not 
give  the  slightest  immunity  from  stiffness. 

Thus  all  the  results  obtained  by  accessory  means,  such 
as  regulation  of  diet,  purgations,  and  sweatings,  could 
be  derived  from  muscular  work  alone.  But  then  the 
result  would  be  more  slowly  attained.  We  must  also 
say  that  it  would  be  more  lasting. 

The  changes  observed  in  the  temperament  of  a  living 
being  under  the  influence  of  methodical  training  are  very 
quickly  produced,  but  they  are  very  easily  lost.  Six 
weeks  of  severe  regulation  bring  about  perfect  "  condi- 
tion," but  a  month's  interruption  causes  the  loss  of  all 
the  benefits  of  the  training,  and  a  return  to  the  former 
state. 

Observation  of  ordinary  facts  shows  us  on  the  other 
hand  the  permanence  of  the  modifications  acquired  by 
persistent  muscular  work. 

We  daily  see  men  and  animals  whose  life  is  one  of 
continual  muscular  work,  acquire  in  the  end  the  conforma- 
tion which  is  so  quickly  produced  by  training.  If  there 
then  comes  a  complete  change  in  their  habits,  they  may 
lose  the  attributes  of  the  trained  man,  but  it  will  not 
be  in  a  month  that,  as  in  the  man  mentioned  by  Worth- 
ington,  an  excessive  quantity  of  reserve  tissues  will  be 
produced. 


TRAINING.  221 

When  a  man  has  spent  his  life  in  the  rough  labour  of 
the  fields,  or  in  the  assiduous  practice  of  physical  exer- 
cise, he  rarely  fails  to  keep  a  slim  and  muscular  con- 
formation for  years  after  he  has  f^iven  up  work.  Similarly, 
an  ox  emplo}-ed  in  hard  work  for  a  long  time,  and  then 
prepared  for  eating,  is  fattened  with  difficulty,  and  his 
flesh  remains  firm  and  coriaceous.  In  spite  of  absolute 
rest  and  superabundant  food  his  muscles  cannot  lose  ail 
at  once  the  hardness  gained  by  long  labour. 

II. 

If  we  examine  a  man  modified  by  the  preparations  we 
have  just  summarily  described,  we  shall  see  that  profound 
changes  have  occurred-  in  his  system  which  have  made 
of  him,  so  to  speak,  a  new  being.  He  differs  in  the 
structure  of  his  tissues,  in  the  conformation  and  in  the 
working,  of  his  organs,  from  his  condition  before  he  began 
training. 

From  the  physiological  standpoint,  the  essential  cha- 
racter of  the  trained  man,  is  the  increase  in  the  tissues 
whose  purpose  it  is  to  move  the  body,  and  the  almost 
complete  disappearance  of  those  which  simply  have  to 
feed  the  combustions  without  which  movement  would  be 
impossible. 

A  trained  man  may  be  compared  to  a  heat-engine  of 
which  the  machinery  has  been  improved,  but  which 
no  longer  carries  about  a  provision  of  fuel  to  feed  the 
fire.  After  the  training,  the  reserve  materials  have  dis- 
appeared, and  it  is  solely  from  his  food  that  a  man 
obtains  the  materials  necessary  for  sustained  work. 

Thus  we  must  not  confuse  the  power  of  resisting 
fatigue  with  the  power  of  enduring  privations.  The 
racehorse,  so  well  fitted  for  intense  and  prolonged  work, 
supports  ill  a  lack  of  nutriment,  and  cannot  be  kept  on 
the  meagre  rations  which  are  enough  for  a  Breton  nag. 
Similarly  with  a  man  in  training  :  if  there  is  insufficient 
food,  exhaustion  will  be  very  rapid.  On  the  other  hand, 
the  combustions  not  being  fed  by  materials  too  easily 
dissimilated,  produce  less  waste-products.  Fatigue, 
which  results  from  auto-intoxication  of  the  body  by  the 
16 


222  PHYSIOLOGY  OF   BODILY  EXERCISE. 

waste-products   of  combustion,   will   not   be   so    easily 
produced. 

In  a  man  in  perfect  "  condition,"  the  products  of 
excretion  which  are  removed  from  the  body  by  the 
eliminating  organs  will  n-^t  be  the  same  as  before  train- 
ing, for  the  tissues,  the  dissimilation  of  which  gives  rise 
to  them,  will  be  different.  The  lungs  will  eliminate  less 
carbonic  acid  for  an  equal  quantity  of  work,  and  will  no 
longer  eliminate  certain  little-known  gaseous  products, 
which  result  from  the  combustion  of  materials  which 
have  been  too  long  retained  in  the  body.  The  skin  will 
no  longer  exhale  the  volatile  fatty  acids,  the  smell  of 
which  is  sometimes  so  marked  in  persons  of  sedentary 
life.  The  kidneys,  after  intense  muscular  work,  will  no 
longer  eliminate  the  excess  of  urates  and  other  nitro- 
genous waste-products  which  are  found  in  the  urinary 
deposits,  and  which  are  so  abundant  in  untrained  persons 
attacked  by  stiffness. 

Hygienists  have  long  pointed  out  the  fact  that  all 
the  excretions  vary  in  a  striking  manner  in  different 
individuals,  according  to  their  mode  of  life.  The  ex- 
halations of  human  beings  have  even  a  different  smell, 
according  as  they  emanate  from  a  man  who  is  in  the 
habit  of  performing  muscular  work,  or  a  man  who  leads 
a  very  sedentary  life.  The  odour  of  a  prison  has  been 
said  to  differ  characteristically  from  that  of  a  barrack. 
Both  result  from  volatile  products  eliminated  by  the 
lungs  and  skin  of  a  great  number  of  men  crowded 
together  ;  but  the  men  of  one  class  have  led  an  inactive 
life,  the  others  have  been  in  continual  activity. 

We  may  certainly  say  that  the  system  of  the  trained 
person  has  undergone  sufficiently  profound  changes  to 
make  of  him  a  being  physiologically  very  different 
from  another  who  has  not  undergone  the  same  training. 
His  conformation  is  different,  the  structure  of  his  tissues 
has  changed.  His  organs  have  undergone  a  transforma- 
tion and  their  working  is  no  longer  the  same. 

The  person  modified  by  training,  and  he  who  has  led 
an  exceedingly  sedentary  life,  must  be  considered,  from 


TRAINING.  223 

a  standpoint  of  observation  and  experiment,  as  very 
different  physiological  units.  If  we  place  them  in  iden- 
tical conditions,  in  which  they  are  submitted  to  modi- 
fying agents,  they  will  not  react  in  the  same  manner. 
Work,  in  especial,  will  modify  in  a  different  manner  the 
working  of  all  their  organs.  For  the  same  number  of 
kilogrammes  of  work  done  in  a  given  time,  we  shall 
not  observe  in  them  a  like  quickening  of  pulse  and  res- 
piration ;  the  air  they  expire  will  not  contain  the  same 
quantity  of  carbonic  acid  ;  their  urine  will  not  eliminate 
the  same  quantities  of  uric  acid. 

Hitherto  insufficient  notice  has  been  taken  of  the 
profound  changes  produced  in  the  results  of  work  by 
the  transformation  undergone  by  the  organism  in  be- 
coming habituated  to  muscular  exercise.  The  greater 
number  of  the  observations  made  on  men  to  estimate 
the  products  of  excretion  resulting  from  w^ork,  are 
fallacious,  owing  to  the  fact  that,  the  influence  of  this 
important  factor  has  not  been  taken  into  account,  the 
condition  of  training  of  the  subject. 

This  is  doubtless  the  cause  of  the  great  differences 
amongst  authors  who  have  examined  the  effect  of  work 
on  the  excretions,  especially  on  the  urine. 


PART     IV. 
THE    DIFFERENT    EXERCISES. 

PHYSIOLOGICAL  CLASSIFICATION  OF  EXERCISES — 
VIOLENT  EXERCISES — EXERCISES  OF  STRENGTH 
— EXERCISES  OF  SPEED — EXERCISES  OF  ENDUR- 
ANCE— MECHANISM   OF   DIFFERENT    EXERCISES. 


CHAPTER  I. 
PHYSIOLOGICAL  CLASSIFICATION  OF  BODILY  EXERCISES. 

Quantity  of  Work  done  in  an  Exercise— Gentle,  Moderate,  and 
Violent  Exercises — Quality  of  Work  in  Exercise — Exercises  of 
Strength,  of  Speed,  and  of  Endurance. — Mechanism  of  the 
various  Exercises. 

We  have  just  studied  the  general  effects  of  muscular 
work  on  *the  organism  which  performs  it.  If  we  en- 
deavour to  sum  up  the  conclusions  to  be  derived  from 
this  study,  we  see  that  the  results  of  work  vary  accord- 
ing to  the  quantity  done  and  the  method  in  which  it  is 
done. 

Exercise  performed  without  moderation  or  rule  in- 
duces all  forms  and  all  degrees  of  fatigue,  and  exposes 
the  human  machine  to  the  various  injuries  which  we 
have  described  as  the  accidents  of  work. 

On  the  other  hand,  muscular  work  performed  in 
gradually  increasing  quantity  and  according  to  the  rules 
of  graduated  training,  brings  about  a  progressive  adap- 
tation of  the  organs  to  the  performance  of  more  and 
more  vicient  exercise.  It  improves  the  human  motor  by 
giving  to  all  its  m^achinery  a  greater  strength  and  ease 
of  working. 

Such  are  the  results  of  exercise  considered  as  an 
abstract  factor  and  reduced  to  the  quantity  of  work 
represented  by  it.  But  it  is  only  by  a  mental  effort  that 
we  can  isolate  the  work  done  by  the  system,  from  the 
organs  concerned  in  its  performance.  Now  these  organs 
are  not  the  same  in  all  cases,  and  do  not  work  in  the 
same  manner  in  all  form.s  of  exercise.  Thus  the  pr?ic- 
tice  of  different  exercises  produces  different  effects  on 
the  system. 


228  PHYSIOLOGY  OF   BODILY   EXERCISE. 

Hence  the  use  of  a  rational  classification  of  the 
different  exercises,  and  the  necessity  of  making  a  choice 
from  among  them  in  accordance  with  the  effects  desired. 

At  the  outset  we  notice  a  difference  between  the 
various  exercises  practised  :  they  do  not  all  necessitate 
the  same  quantity  of  work.  Exercises  are  called 
violent  when  they  demand  considerable  and  repeated 
efforts  from  the  muscular  system  ;  they  are  called 
moderate  when  they  do  not  demand  much  work  :  finally, 
when  the  muscular  exertion  is  reduced  to  a  minimum, 
the  exercise  is  called  gentle.  Running  is  a  violent 
exercise,  walking  at  a  fair  pace  is  a  moderate  exercise, 
and  walking  slowly  is  a  gentle  exercise. 

The  quantity  of  work  done  is  evidently  the  chief 
element  in  the  classification  of  bodily  exercises,  for  it 
is  that  which  most  influences  their  effects.  But,  the 
amount  of  work  done  by  the  system  being  the  same,  it 
is  not  indifferent,  from  the  hygienic  standpoint,  whether 
the  work  is  done  slowly  or  quickly,  whether  it  is  unin- 
terrupted, or  there  are  frequent  periods  of  rest.  It  is 
important  also  to  know  if  the  exercise  needs  complicated 
and  difficult  movements,  if  it  exacts  great  attention  of 
the  will,  or  if  it  can  be  performed  automatically,  and 
without  needing  the  intervention  of  the  conscious 
faculties. 

Finally,  besides  the  different  forms  of  the  work,  it  is 
also  important  to  determine  the  mechanism  of  the  exer- 
cise, to  say  what  parts  of  the  body  are  especially 
concerned  in  its  performance,  and  what  are  indirectly 
associated  with  it.  This  is  one  of  the  least  known 
points  in  the  therapeutics  of  exercise,  for  the  analysis  of 
the  different  exercises  of  the  body  has  not  yet  been 
made  in  a  satisfactory  manner.  It  is  however  one  of 
the  most  interesting  and  most  practical  points  in  this 
branch  of  hygiene,  for  upon  the  intimate  mechanism  of 
an  exercise  depend  its  local  effects.  A  bodily  exercise 
is  often  prescribed  with  an  orthopaedic  object,  but  we 
cannot  exactly  foresee  its  effects  unless  we  know  exactly 
which    group    of    muscles    performs   the   work,  which 


PHYSIOLOGICAL    CLASSIFICATION    OF    EXERCISES.     229 

articulations  and  which  bony  levers  support  the  pres- 
sures and  the  shocks,  and  by  what  attitudes  the  whole 
of  the  body  associates  in  the  movement  of  the  regions 
at  work. 

A  physiological  classification  of  bodily  exercises, 
taking  especially  into  account  the  effects  produced  on 
the  system  by  the  different  exercises,  must  have  for  its 
basis  three  elements  :  the  quantity  of  work  which  they 
need,  the  nature  or  quality  of  this  work,  and  finally  the 
viecJianism  by  the  aid  of  which  the  work  is  performed. 
But  these  three  elements  of  classification  are  combined 
in  so  varied  a  manner  in  the  different  exercises  practised, 
that  they  cannot  logically  serve  for  their  grouping. 
Some  exercises  allied  by  the  quantity  of  work  they 
represent,  differ  in  the  mechanism  of  their  performance  ; 
others,  on  the  contrary,  are  similar  as  regards  move- 
ments, but  differ  in  the  intensity  of  the  work. 

So  these  three  elements,  quantity^  quality^  and  mechan- 
ism of  work,  will  not  be  taken  here  as  the  basis  of  a 
systematic  classification  of  exercises.  They  will  rather 
serve  as  landmarks  to  guide  us  in  the  physiological 
analysis  of  these  exercises,  and  as  labels  for  their  group- 
ing in  categories  corresponding  to  certain  effects,  now 
salutary,  now  harmful,  according  as  they  conform  to,  or 
are  in  opposition  to,  the  indications  furnished  by  the 
temperament  and  morbid  state  of  the  patient 


CHAPTER    IL 

VIOLENT  EXERCISES. 

Violent  Exercise  must  not  be  confounded  with  Fatiguing  Exercise 
— Difficulty  of  appreciating  the  Quantity  of  Work  expended 
in  an  Exercise — Difficult  Movements —Feats  of  Strength — 
Gymnastic  Pedants -Children's  Games  and  Gymnastics — Skip- 
ping compared  with  Climbing  a  Rope — Analysis  of  Exercises 
• — How  the  Physiological  Effects  of  Work  may  indicate  its 
Degree  of  Intensity. 

The  quantity  of  work  represented  by  an  exercise  is  the 
basis  of  the  classification  of  bodily  exercises  into  gentle^ 
moderate^  and  violent. 

This  division  appears  at  first  very  logical  and  extremely 
easy  to  establish,  but  an  attentive  analysis  is  sometimes 
necessary  to  determine  the  real  expenditure  of  force  re- 
presented by  an  exercise.  The  estimation  is  often,  and  er- 
roneously, based  on  the  difficulty  experienced  in  perform- 
ing the  work  or  on  the  fatigue  felt  by  the  muscles  en- 
gaged. Now  it  may  happen  that  the  expenditure  of  force 
necessitated  by  an  exercise  is  masked  by  the  ease  with 
which  the  muscular  action  is  performed.  It  may  happen 
that  an  insignificant  work  produces  a  lively  sensation  of 
fatigue.  It  is  always  easy,  even  to  a  very  heavy  man,  to 
go  up  ten  steps  of  a  staircase.  But  he  would  often  find 
it  very  difficult  to  go  up  ten  rungs  of  an  inclined  ladder 
hanging  by  his  hands.  Still,  if  the  vertical  distance 
between  the  rungs  and  that  between  the  steps  is  the 
same,  the  mechanical  work  is  strictly  the  same  in  the  two 
cases,  for  it  represents  an  expenditure  of  force  capable  of 
raising  the  same  weight  through  the  same  height.  The 
fatigue  experienced  is  however  much  greater  after  going 
up  the  ladder  than  after  going  up  the  stairs.  This  is 
because  in  the  first  case  the  work  has  been  done  by  the 
small  muscles  of  the  upper  limbs,  and  in  the  second  case 
by  the  powerful  muscular  masses  of  the  lower  limbs. 

Neither   the    difficulty  of  an   exercise  nor    the  local 


VIOLENT    EXERCISES.  23 1 

fatigue  caused  by  it  can  serve  as  a  basis  for  determining 
the  quantity  of  work  done. 

Violent  exercise  is  often  wrongly  confused  with  a 
"  feat  of  strength,"  or  a  "  difficult  "  exercise.  In  all  feats 
of  strength  it  may  happen  that  the  work,  without  being 
considerable,  may  be  executed  by  means  of  a  very  small 
number  of  muscles.  The  exercise  is  then  merely  a  kind 
of  demonstration  of  the  muscular  strength  of  the  indivi- 
dual, who  for  example  performs  with  ten  m.uscles  a  work 
v/hich  other  people  can  only  do  with  twenty.  A  m.an  who 
seizes  a  horizontal  bar  with  one  hand  and  raises  himself  with 
only  one  arm,  shows  that  he  has  a  very  strong  biceps,  but 
the  mechanical  work  he  performs  is,  in  the  end,  strictly  equal 
to  that  done  by  a  man  who  pulls  himself  up  with  both  arms, 

Som.etim.es  so-called  feats  of  strength  are  only  feats  of 
skill.  In  gymnastics  there  are  many  movements  which 
need  a  long  apprenticeship  and  which  in  the  end  can  be 
performed  v/ith  the  expenditure  of  an  insignificant 
amount  cf  force  when  a  man  has  learned  the  trick. 
The  difficulty  in  the  performance  of  these  exercises  does 
not  consist  in  the  expenditure  of  very  great  muscular 
force,  but  in  finding  from  experience,  or  from  teaching, 
the  muscles  which  must  be  thrown  into  action.  Numerous 
movements  performed  on  the  trapeze,  and  in  "  German  " 
gymnasia,  need  more  science  than  strength. 

We  must  not  confuse  "  quantity  of  work  "  with 
"difficulty  of  work."  This  is  a  mistake  of  daily 
occurrence,  and  the  result  is  that  the  preference  is 
given  from  the  hygienic  standpoint  to  exercises  which 
are  m.erely  clever,  while  the  really  violent  exercises 
are  abandoned,  being  those  in  which  force  is  expended, 
without  any  laborious  calculation  how  to  use  it. 

Now  the  general  effects  of  exercises  are  in  proportion 
to  the  expenditure  of  force  which  the  exercise  renders 
•necessary,  and  not  to  the  difficulties  presented  by  the 
details  of  its  execution. 

In  our  day  the  trapeze  seems  almost  to  be  considered 
as  the  regenerator  of  the  human  species.  It  seems  that 
the  art  of  moving  the  limbs  can  only  be  acquired  after 
long  researches  and  profound  meditations.     We  fall  under 


232  PHYSIOLOGY  OF  BODILY  EXERCISE. 

the  rod  of  the  gymnastic  pedants,  and  doubtless  a  time  will 
come  when  we  shall  be  as  astonished  at  taking  exercise 
in  walking  as  M.  Jourdain  was  at  talking  prose  in 
speaking.  By  young  men,  and  even  in  girls'  board- 
ing schools,  we  see  the  most  complicated  machinery  used 
and  the  most  difficult — we  might  say  the  most  grotesque 
— movements  performed.  For  want  of  an  attentive 
analysis  people  do  not  understand  that  many  of  the 
games  of  young  children  are  in  reality  violent 
exercises,  while  many  of  the  exercises  of  the  orthodox 
gymnast  are  merely  feats  of  skill. 

We  may  prove  by  figures  that  the  expenditure  of  force, 
the  end  to  be  obtained  by  gymnastics,  is  greater  in  certain 
children's  games  than  in  certain  exercises  of  the  gymna- 
sium which  seem  to  demand  exceptional  strength. 

Let  us  suppose  that  a  little  girl  is  amusing  herself  by 
skipping.  It  is  easy  to  jump  o.i  metre  high  lOO  times 
a  minute.  The  work  done,  therefore,  will  be  equal  to 
an  expenditure  of  force  capable  of  raising  her  body  to  a 
height  of  lo  metres.  Now  there  are  not  many  gymnasts 
who  could  climb  with  their  hands  alone  to  a  height  of 
I O  metres  in  a  minute;  there  is  not  probably  one  who 
could  go  on  climbing  for  three  minutes  at  this  pace, 
while  there  are  many  little  girls  v/ho  can  skip  for  five 
minutes  or  more  without  stopping. 

In  the  act  of  skipping,  the  work  is  not  done  by  the 
same  muscles  which  are  used  in  climibing  a  rope,  so  the 
local  effects  of  the  two  exercises  will  be  different.  But 
if  in  both  exercises  the  number  of  kilogrammetres  of 
work  done  is  the  same,  the  general  effects  of  the  work 
will  be  identical,/br  tJie  changes  in  the  great  organic  func- 
tions, and  particularly  the  cJianges  in  breatJiing^  are  in  aired 
ratio  to  the  siun  total  of  work  done  in  a  given  time.  Now, 
in  the  application  of  exercise  to  hygiene,  the  general 
effects  of  work  are  especially  sought  ;  we  wish  to  render 
the  blood  current  more  active,  to  increase  the  power  of 
the  respiratory  movements,  and  in  a  word  to  associate  all 
the  great  organic  functions  of  the  economy  in  the  work. 

It  is  not  always  easy  to  estimate  the  quantity  of 
work  represented    by  an    exercise.     The    effort  is    not 


VIOLENT    EXERCISES.  233 

always  apparent,  and  does  not  always  show  itself  in 
moving-  the  body.  In  certain  cases  the  force  expended 
by  a  man  has  its  effect  negatived  by  an  equal  force 
expended  by  an  adversary.  We  see  this,  for  instance, 
in  wrestling.  In  other  cases  the  apparent  work  is  not 
increased,  but  the  expenditure  of  force  is  rendered 
greater  by  the  unfavourable  arrangement  of  the  bony 
levers  which  perform  the  movement.  Thus  the  exercise 
of  making  a  plank,  only  needs  to  sustain  the  weight  of 
the  body  by  the  strength  of  the  arms  ;  but  the  horizontal 
attitude  taken  by  the  trunk  and  limbs  increases  tenfold 
the  expenditure  of  muscular  force,  and  consequently 
increases  the  violence  of  the  exercise. 

It  would  need  too  lengthy  an  analysis  to  find  the 
exact  amount  of  work  in  kilogrammetres  demanded  by 
each  exercise,  and  the  changes  in  this  amount  produced 
by  different  methods  of  performance.  It  will  be  enough 
to  repeat  that  there  are  artifices  for  diminishing  the 
expenditure  of  force  in  any  exercise,  and  other  artifices 
for  increasing  it.  There  are  movements  which  make 
use  of  the  impetus  derived  from  the  speed  of  the  body, 
and  there  are  others  which  suppress  all  impetus,  and 
force  antagonistic  muscles  to  hinder  the  action  of  the 
muscles  which  are  doing  the  work,  and  to  make  the 
movements  slower.  In  this  manner  slowness  in  the 
performance  of  a  muscular  action  may  much  increase 
the  expenditure  of  force  ;  to  stoop  quickly  we  have 
merely  to  relax  all  the  muscles  of  the  thigh,  whereas 
if  we  wish  to  stoop  very  slowly  we  must  keep  the 
extensor  muscles  in  vigorous  action  in  order  to 
sustain  the  weight  of  the  body,  and  to  maintain  it  in 
successive  attitudes  of  descent  by  acting  on  levers 
placed  at  a  very  unfavourable  angle. 

It  is  important  to  determine  the  real  quantity  of  work 
done  in  an  exercise  and  to  distinguish  a  violent  exercise 
from  a  difficult  exercise  or  a  "  feat  of  strength,"  for  the 
efforts  are  very  different  in  the  two  cases. 

In  a  "  feat  of  strength  "  the  quantity  of  work  done  by 
the  organism    may  be    quite    small,  but   generally  the 


234  PHYSIOLOGY    OF    BODILY    EXERCISE. 

local  work  is  very  considerable  in  relation  to  the 
strength  of  the  muscles  which  perform  it.  The  effect 
of  the  exercise  is  then  especially  local,  and  may  perhaps 
have  no  appreciable  influence  on  the  whole  system. 
By  continual  practice  in  raising  weights  with  the  arm 
outstretched  it  is  possible  very  greatly  to  develop  the 
muscles  which  extend  the  arm  on  the  shoulder  ;  but 
the  great  organic  functions,  respiration,  circulation, 
etc.,  will  participate  very  little  or  not  at  all  in  the 
work.  The  exercise  will  represent  an  expenditure 
of  force  capable  of  rapidly  tiring  the  few  muscles  in 
action,  but  not  enough  to  have  much  influence  on  the 
blood-current  or  the  movements  of  the  lungs. 

In  a  difficult  exercise,  the  performance  of  which  needs 
the  perfect  co-ordination  of  movement,  the  exact 
weighing  of  the  effort  of  each  m.uscle,  the  chief  expen- 
diture will  be  of  nervous  energy,  and  the  muscles  will 
only  perform  a  feeble  mechanical  work.  The  nerve 
centres  will  then  have  more  to  do  with  the  exercise  than 
the  muscular  fibres  ;  the  psychical  faculties  will  come 
more  into  play  than  the  muscular  strength. 

Gymnastics,  as  now  carried  on  at  educational  establish- 
ments in  France, make  a  man  v/ho  devotes  him^self  to  them, 
spend  most  of  his  time  in  a  long  apprenticeship  and  in  true 
mental  work.  The  trapeze,  the  horizontal  bar  and  the  rings, 
are  things  on  v/hich  feats  of  skill  are  done,  rather  than 
work,  in  the  mechanical  sense  of  the  word.  Many  pupils 
spend  months  in  learning  a  breast  or  a  balance^  and  when 
they  discover  the  method,  the  muscular  trick,  they  do  all 
at  once  v/ith  the  greatest  ease  the  muscular  action  which 
the  day  before  seemed  to  be  beyond  their  strength. 

If  v/e  try  to  sum  up  what  we  have  explained  in  this 
chapter,  we  shall  com.e  to  the  conclusion  that  it  is  not 
always  easy  to  estim.ate  at  the  first  glance  the  amount 
of  work  done  during  an  exercise,  and  to  determine  the 
degree  of  "violence"  of  this  exercise.  Neither  the 
diiificulty  in  the  performance  of  the  movements,  nor  the 
local  effort  they  needj  are  characteristic  of  the  intensity 
of  the  v/ork,  and  a  rigorous  analysis  is  often  necessary 
to  estimate  the  expenditure  of  force. 


VIOLENT    EXERCISES.  235 

But,  failing  a  mechanical  analysis,  the  physiological 
effects  of  an  exercise  may  serve  to  help  us  to  appreciate 
the  degree  of  violence.  The  great  vital  functions  are 
more  energetically  associated  v/ith  muscular  exercise  in 
proportion  to  the  greater  intensity  of  the  v/crk. 

We  have  shown  in  the  chapter  on  Breaihlessness  the 
close  relation  between  increase  of  the  respiratory  need 
and  increase  of  muscular  v/ork.  The  energy  and  the 
frequency  of  the  m.ovements  of  the  heart  increase 
according  to  the  same  laws.  The  quickening  of 
respiration  only  becomes  excessive  m  exercises  deter- 
mining a  great  expenditure  of  force.  Muscular  fatigue 
may,  on  the  other  hand,  be  severe  without  the  amount 
of  work  done  being  considerable  ;  in  the  case  for  instance 
in  which  the  v/ork  is  done  by  a  small  number  of  miuscles. 

The  form)  taken  by  fatigue  after  exercise,  may  give, 
physiobgicaily,  a  m^easure  oï  the  v/ork  done  in  a  given 
time.  The  muscular  fatigue  of  any  region  of  the  body 
may  serve  to  estimate  the  intensity  of  the  local  work  ; 
the  measure  of  the  total  work  will  be  given  by  the 
violence  of  the  disturbances  cf  the  heart  and  lungs,  that 
is  to  say,  the  intensity  cf  breathlessness  and  the  quicken- 
ing of  the  pulse. 

The  measure  we  suggest  can  evidently  only  be  applied 
to  the  samie  individual,  or  to  two  individuals  equal  in  power 
of  resistance,  in  strength,  and  in  habituation  to  work  ;  but 
v/ith  this  restriction  we  can  adopt,  as  a  criterion  of  classi- 
fication, the  following  indication  : — 

V/hen,  after  an  exercise,  a  m.an  of  average  strength 
has  experienced  neither  fatigue  nor  breathlessness,  the 
exercise  may  be  called  gentle.  When  the  exercise  has 
caused  local  fatigue  without  inducing  breathlessness,  it 
will  be  moderate.  It  will  be  called  vicient  v/hen  it  is 
accompanied  and  followed  by  breathlessness. 

This  division  seem.s  to  us  to  be  the  best  from  the 
physiological  standpoint  ;  it  is  not  based  upon  the 
difficulty  of  the  exercise  but  on  the  physiological  reaction 
of  the  system..  Nov/  this  reaction  is  alv/ays,  in  the  same 
person,  in  proportion  to  the  quantity  of  work  performed 
by  the  organs  in  a  given  time. 


CHAPTER  m. 

EXERCISES   OF  STRENGTH. 

Gymnastics  —  Frequent  Intervention  of  Effort  in  Exercises  of 
Strength — Why  it  is  Impossible  to  have  "  a  Smile  on  the 
Lips  "  in  practising  an  Exercise  of  Strength — Charles  Bell  on 
the  Facial  Movements — Intensity  of  Breathlessness  in  Exercises 
of  Strength — Wrestling — Advantages  of  Exercises  of  Strength. 
Their  superiority  to  Exercises  of  Speed  for  Increasing  the  size 
of  the  Body — Inconveniences  of  Exercises  of  Strength.  Danger 
of  Effort  :  Frequency  of  Hernia  ;  Frequency  of  Rupture  of 
Blood-vessels — Overwork  and  Exhaustion  in  Forced  Labours. 

L 

We  call  exercises  of  strength  those  in  which  each 
movement  represents  a  great  quantity  of  work,  and 
brings  into  play  the  contractile  power  of  a  great  number 
of  muscles. 

The  lifting  and  carrying  of  heavy  burthens  is  the 
type  of  works  of  strength,  and  it  is  really  in  the  hard 
manual  professions  that  we  can  best  study  their  effects. 

Evidently  the  movements  of  gymnastics,  whose  usual 
object  it  is  to  displace  the  body  in  various  directions, 
cannot  give  rise  to  muscular  efforts  as  intense  as  those 
of  a  man  who  displaces  at  the  same  time  a  heavy  burthen 
and  his  own  body.  And,  in  fact,  gymnastic  exercises 
are  rarely  exercises  of  strength.  There  are,  however, 
movements  performed  with  the  aid  of  apparatus,  which 
seem  at  first  to  need  an  enormous  expenditure  of  force, 
owing  to  the  unfavourable  positions  in  which  the  bony 
levers  act  ;  but  we  soon  see  that  muscular  effort  in  these 
movements  is  in  direct  ratio  to  the  inexperience  of  the 
gymmast.  By  practice  we  are  always  able  to  discover  a 
process  which  facilitates  the  performance.     The  humas 


EXERCISES    OF    STRENGTH,  237 

machine  represents  an  articulated  system  made  up  of  a 
great  number  of  movable  pieces  joined  together.  Hence 
there  is  an  infinite  number  of  combinations  of  attitudes 
Often  an  imperceptible  variation  in  the  direction  of  a 
limb  totally  changes  the  conditions  of  the  work.  An 
undiscoverable  variation  in  the  performance  of  a 
breasting  movement  diminishes  by  nine-tenths  the 
expenditure  of  force.  Thus  an  exercise  which  at  the 
outset  seemed  athletic,  only  needs,  after  some  months' 
practice,  very  moderate  work. 

Exercises  of  strength  may  be  better  studied  among 
wrestlers  than  among  gymnasts.  They  form  what  may 
be  called  athletic  gymnastics,  and  wrestling  is  perhaps 
now  the  only  bodily  exercise  which  can  be  placed  in 
this  category  :  skill  and  trick  have,  however,  a  great 
place  in  this  sport. 

The  exercises  in  which  a  man  must  employ  his  whole 
strength  need  the  intervention  of  two  factors  :  the 
muscles  and  the  v/ill.  It  is  especially  in  these  exercises 
that  we  can  understand  the  importance. of  nervous  energy 
as  an  agent  of  work.  Two  men  who  are  equally  well 
endowed  in  the  matter  of  physical  conformation,  and 
completely  equal  as  regards  their  muscles,  will  often 
show  a  very  considerable  difference  in  exercises  of 
strength.  We  may  predict  with  certainty  that  the  ad- 
vantage will  lie  with  the  one  whose  will  is  m^ost  energetic, 
for  this  energy  is  manifested,  on  the  physical  side,  by  a 
more  intense  stimulation  of  the  muscles,  and  hence  by  a 
more  powerful  contraction. 

The  exercises  of  strength  demand  the  simultaneous 
action  of  a  great  number  of  muscles.  They  demand, 
further,  that  every  muscle  in  action  should  bring  its 
whole  force  into  play  :  for  this  it  is  necessary  that  the 
muscle  should  take  a  very  firm  attachment  to  a  fixed 
point  of  the  skeleton.  Now  the  bones  of  the  skeleton 
being  movable  on  each  other,  it  is  necessary,  as  a  pre- 
paration for  athletic  movements,  that  all  the  bony  pieces 
should  be  strongly  united  by  a  vigorous  pressure  to 
make  up  a  rigid  whole.  This  necessity  of  soldering 
17 


238  PHYSIOLOGY    OF    BODILY    EXERCISE. 

together,  as  it  were,  a  number  of  movable  pieces  to 
make  a  resistant  v/hole,  is  a  very  characteristic  point 
of  the  physiology  of  exercises  of  strength.  Athletic 
gymnastics  inriplies  the  frequent  intervention  of  the 
action  called  Effort. 

We  described  effort  at  length  in  the  second  chapter  cf 
the  first  part  of  this  book,  and  explained  the  modifica- 
tions of  respiration  which  result  from  it.  Effort  m.ay  be 
called  the  characteristic  sign  of  exercises  of  strength. 
It  is  im.possible  for  a  man  to  use  his  whole  strength 
without  the  production  of  that  violent  contraction  of  all 
the  m.uscles  of  the  trunk  v/hose  object  it  is  to  render  the 
ribs  motionless,  and  which  results  in  the  stoppage  of 
respiration.  If  a  man  has  to  raise  from  the  ground  a 
very  heavy  burthen,  we  are  struck  by  seeing  the  whole 
body  stiffen  from  head  to  foot,  and  all  the  bones  pressed 
together  by  the  energetic  contraction  of  the  muscles 
attached  to  them.  Each  limb,  made  up  of  two  or  three 
segments,  seems  now  to  form  one  rigid  piece  ;  the  trunk, 
neck,  and  head,  share  in  the  general  rigidity,  and  even 
the  muscles  of  the  face  are  violently  contracted  during 
an  effort,  though  it  is  difîficult  at  first  to  account  for  the 
share,  for  instance,  of  the  eyelids  and  cheeks  in  the  action 
of  lifting  a  bale  of  goods  on  to  the  shoulders. 

The  drawn  face  of  a  man  momentarily  using  his  whole 
strength  is  a  matter  of  common  observation.  We  re- 
member hearing  the  boast  of  a  strong  man  at  a  fair  that 
he  would  hold  out  a  heavy  load  at  arms'  length  "  with  a 
smile  upon  his  lips."  He  did  it,  but  the  pretended  smile 
was  merely  a  grin  in  which  the  eyebrows  and  eyelids 
took  no  part,  being  contracted  in  association  with  the 
efibrt.  The  physiologist,  Charles  Bell,  long  ago  gave  a 
reason  for  this  association  of  the  muscles  about  the  eyes, 
with  effort.  During  effort,  the  flow  of  blood  in  the 
orbital  vessels  causes  them  to  swell  up,  and  to  project 
the  globe  forwards.  The  muscles  in  front  of  the  orbit 
contract  instinctively  in  order  to  support  the  globe,  and 
to  check  its  protrusion. 

The  first  effect  of  an  exercise  of  strength  should  be  to 
induce  quickly  fatigue  of  the  muscles  from  which  enor- 


EXERCISES    OF    STRENGTIL  239 

mous  work  is  suddenly  demanded.  But  breathlessness 
precedes  fatigue  in  the  course  of  these  exercises.  How- 
ever slow  the  movements,  respiration  is  very  quickly 
embarrassed,  and  the  v/restler  or  the  porter  vv^ith  a  heavy 
burthen  must  often  stop  for  breath,  long  before  their 
m.uscles  are  fatigued. 

We  explained  at  length,  in  the  chapter  on  Breathless- 
ness, the  mechanism  of  this  respiratory  distress  after 
great  expenditure  of  muscular  force.  The  muscles  in 
action  produce  carbonic  acid  in  proportion  to  the  inten- 
sity of  the  work  done.  In  the  exercises  of  strength  there 
is  produced  in  the  system  at  every  miovement,  more  car- 
bonic acid  than  the  lungs  can  elimanate,  and  the  surcharge 
of  the  blood  with  carbonic  acid  induces  dyspnœa. 

Further,  effort  has  a  very  powerful  influence  in  in- 
ducing respiratory  distress  in  exercises  of  strength. 
This  action  causes  a  stoppage  of  breathing  during  the 
whole  time  occupied  by  the  muscular  contraction  :  it 
thus  hinders  the  elimination  of  carbonic  acid  just  at  the 
time  when  this  gas  is  being  produced  in  excessive 
quantity.  It  further  leads  to  violent  compression  of  the 
great  veins  of  the  thorax,  of  the  great  arteries,  and  of 
the  heart  itself,  and  produces  profound  disturbances  in 
the  pulmonary  circulation,  the  regularity  of  which  is  an 
essential  condition  of  aeration  of  the  blood. 

Among  bodily  exercises  there  is  one  which  may  be 
considered  as  the  type  of  exercises  of  strength  :  this  is 
wrestlifig.  If  two  wrestlers  who  understand  each  other 
are  making  a  pretty  looking  play  before  the  public, 
wrestling  is  rather  an  exhibition  of  agility  and  suppleness 
than  an  athletic  exercise.  But  if  the  adversaries,  using 
all  their  strength,  seek  to  overthrow  each  other,  there  is 
an  enormous  expenditure  of  muscular  force.  Very  con- 
siderable muscular  efforts  may  be  m.ade  without  apparent 
work,  that  is  to  say,  without  the  bodies  of  the  v/restlers 
making  any  movement.  The  thrust  of  one  of  them  is 
paralysed  by  the  resistance  of  the  other,  until  the  stronger, 
maintaining  his  most  powerful  contraction,  causes  weari- 
ness in  the  weaker,  who,  at  the  end  of  his  resources,  yields 
and  falls. 


240  PHYSIOLOGY    OF    BODILY    EXERCISE. 

At  this  moment  we  observe  in  both  men  an  extreme 
degree  of  breathlessness.  A  wrestler  who  is  beaten  has 
respiratory  disturbances  as  intense  as  those  of  a  runner 
who  stops  for  want  of  breath.  Wrestling  is  not  merely 
an  assault  of  brute  force  ;  it  has  its  feints,  attacks  and 
tricks.  But  the  characteristic  of  this  exercise  is  the 
necessity  of  throwing  into  the  movements  of  attack  and 
defence  a  man's  whole  strength,  so  that,  even  for  the 
cleverest  wrestlers,  this  exercise  always  demands  a  great 
expenditure  of  force,  and  is  the  most  brutal  of  all  bodily 
exercises.  It  is  the  exercise  in  which  the  quantity  of 
muscle  is  the  essential  element  of  success.  It  is  thus  the 
one  which  has  most  tendency  to  develop  muscle  and  to 
increase  the  weight  of  the  body,  for  every  exercise  tends 
to  give  to  the  body  the  conformation  which  makes  this 
the  fitter  for  its  performance. 

II. 

Exercises  of  strength  demand  great  muscular  ex- 
penditure, but  they  produce  all  the  conditions  necessary 
for  energetic  tissue-repair.  They  need  very  little  work  of 
co-ordination  and  do  not  demand  a  frequent  repetition  of 
movement.  They  occasion  less  disturbance  in  the  nerves 
than  exercises  of  speed,  and  do  not  demand,  like  exercises 
of  skill,  great  brain  work. 

Forced  labour  is  nearly  always  performed  by  the  aid 
of  slow  and  sustained  contraction.  The  muscular  fibre 
of  a  wrestler  is  tense  in  one  direction  for  sometimes  an 
entire  minute  ;  the  muscles  of  a  fencer  are  changing  every 
moment  from  repose  to  action,  and  moving  the  limbs  in 
the  most  varied  directions.  Powerful  and  sustained  con- 
tractions favour  the  nutrition  of  the  muscular  fibre.  The 
nutrition  of  muscle  is  more  intense  in  slow  contractions, 
because  the  flow  of  blood  is  more  regular  and  more 
prolonged. 

Exercises  of  strength  and  forced  labour^  in  spite  of 
the  great  quantity  of  work  ttey  need,  have  little 
influence  on  the  brain,  they  affect  the  functions  of 
nutrition  much  more  than  those  of  innervation.  The 
energetic   and   sustained   muscular   contractions    which 


EXERCISES    OF    STRENGTH.  24I 

the)'  render  necessary  draw  blood  to  the  muscles  in 
great  quantity  and  keep  it  there  a  long  time.  The 
muscular  fibres  benefit  from  this,  and  increase  in  size. 
On  the  other  hand  the  blood  is  enriched  with  a  great 
quantity  of  oxygen,  for  increased  respiratory  need  is  the 
first  effect  of  great  expenditure  of  muscular  force.  This 
need  finds  free  and  easy  satisfaction  in  the  period  of 
repose  which  inevitably  follows  each  effort.  Finally  the 
intensity  of  the  combustions  due  to  a  great  quantity  of 
work,  promotes  the  using  up  and  prompt  disappearance 
of  the  reserve  materials,  and  the  need  of  quick  repair; 
whence  increased  appetite.  On  the  other  hand  the 
repeated  contractions  of  the  abdominal  muscles  in  the 
frequently  recurring  efforts,  performs  a  sort  of  massage 
on  the  intestines  which  favours  the  onward  movement  of 
the  faeces  and  makes  the  bowels  regular. 

Exercises  of  strength  are  then  favourable  to  all  the 
nutritive  functions.  They  increase  energetically,  and 
even  violently,  the  working  of  all  the  organs  of  the 
body,  while  leaving  in  relative  repose  the  nerve-centres 
and  psychical  faculties.  Now  calm  of  the  nervous 
system  is  a  valuable  condition  for  the  repair  of  the  losses 
sustained  in  work. 

Observation  of  facts  shows  that  athletic  exercises, 
when  they  are  not  beyond  the  strength  of  the  subject, 
place  him  in  the  most  favourable  conditions  of  nutrition. 
Under  the  guidance  of  a  quiet  nervous  system,  the 
functions  of  repair  are  performed  with  the  most  perfect 
regularity,  and  we  see  that  the  acquisitions  made  by  the 
system  through  more  perfect  assimilation  exceed  the 
losses  brought  about  by  work.  Exercises  of  strength 
tend  to  increase  the  weight  of  the  subject. 

Exercises  of  strength  seem  then  to  deserve  the 
preference  from  the  hygienic  point  of  view,  and  it  is  in 
fact  in  the  professions  in  which  work  is  taken  in  large 
doses  that  we  find  the  most  vigorous  persons.  But  in 
order  to  be  salutary  these  exercises  need  several 
conditions  which  are  not  always  present. 

In  the  first  place  they  must  be  performed  by  solidly 
constructed  organs  which   are  free  from  all   defects  of 


242  PHYSIOLOGY    OF    BODILY    EXERCISE. 

nutrition.  The  muscles,  the  tendons,  the  aponeuroses, 
even  the  bones  undergo  tractions  and  pressures  which 
are  so  violent  that  ruptures  of  all  kinds  would  be 
produced  had  not  a  progressive  state  of  habituation 
gradually  consolidated  them.  Accidents  of  all  kinds, 
rupture  of  muscles,  lacerations,  dislocations,  are 
frequently  seen  during  exercises  of  strength.  Other 
more  serious  lesions,  such  as  hernia,  laceration  of  the 
lung,  rupture  of  great  vessels,  and  even  of  the  heart,  are 
liable  to  occur  unless  the  internal  organs  are  perfectly 
sound.  Organs  which  have  undergone  some  degree  of 
degeneration  are  soon  incapable  of  resisting  the  violent 
strain  of  effort. 

Finally  it  is  necessary,  to  avoid  overwork,  that  the 
work  should  be  gradually  increased  and  not  done  in  the 
largest  quantities  till  after  complete  training.  If  a  man 
who  attempts  an  exercise  of  strength  is  too  freely 
provided  with  reserve  materials,  these  undergo  dis- 
similation in  mass,  and  an  excessive  quantity  of  waste- 
products  is  produced.  This  causes  auto-intoxication  by 
poisonous  substances,  alkaloids  or  others. 

Thus  are  to  be  explained  the  fevers  of  overwork^ 
often  taken  for  typhoid  fever,  in  young  recruits.  Facts 
show  that  these  fevers  have  a  special  predilection  for 
the  services  which  need  forced  labour,  the  Artillery  for 
instance. 

To  perform  exercises  of  strength  with  impunity,  the 
food  must  be  sufficiently  abundant  to  supply  the  losses 
undergone.  If  the  food  is  not  sufficiently  restorative, 
the  work  is  done  at  the  expense  of  the  materials  of 
the  body  ;  the  worker  becomes  thin  and  is  quickly 
exhausted. 

Exhaustion  will  also  result  from  excessive  work  which 
exceeds  a  man's  strength  even  if  he  is  well  fed.  If  a 
man  wishes  to  get  out  of  his  muscles  a  quantity  of  force, 
out  of  proportion  to  their  contractile  power,  he  is  obliged 
to  make  an  energetic  effort  of  will,  and  he  needs  a  great 
expenditure  of  nervous  energy  to  excite  more  power- 
fully the  weak  muscular  fibre.  He  can  thus  perform  a 
work  beyond  his  strength,  but  it  is  by  taking  "from  his 


EXERCISES    OF    STRENGTH.  243 

nerves  "  that  which  his  muscles  are  unable  to  g"ive.  In 
this  case  the  exercise  of  strength  will  not  have  its  usual 
result,  of  economising  nervous  energy.  A  work  of  the 
nerve-centres  is  necessary  to  increase  the  irritability  of 
the  muscles.  We  do  not  know  exactly  in  what  this 
work  consists,  but  v\^e  can  determine  its  effects.  The 
excessive  exertion  of  the  will  in  the  work  leads  quickly 
to  nervous  exhaustion.  The  man  becomes  thin,  eats  and 
sleeps  ill  ;  he  suffers  from  overwork  by  exhaustion.  It 
is  thus  that  we  see  horses  rapidly  v/aste  and  get  ill, 
although  they  are  well  fed,  if  they  are  forced  to  draw 
too  heavy  a  load,  and  their  ardent  and  generous  nature 
impels  them  to  go  on  working  up  to  the  last  limit  of 
their  strength. 


CHAPTER  ÎV. 

EXERCISES   OF   SPEED. 

Accumulatt'oh  of  Work  by  the  rapid  Succession  of  Movements. 
Common  re.vu'ts  of  works  of  Strength  and  Exercises  of  Speed  ; 
the  "Thirst  lor  Air";  Breathlessness  —  Strength  and  Speed 
combined — "  Forced  "  Exercise  ;  its  Dangers — Part  played  by 
the  Nervous  System  in  Exercises  of  Speed— Law  of  Helmholtz; 
the  Loss  of  Time  in  Muscle  ;  "  Latent  Period  " — Irritability  ol 
Muscle  ;  its  pirt  in  Exercises  of  Speed  ;  its  Variability  in 
different  Kinds  of  Animals  ;  the  Snail  and  the  Bird — Its  Varia- 
bility in  different  Individuals  and  different  Nations  :  Dutch 
Rowers — Effects  of  Exercises  of  Speed— Effects  due  to  the 
Accumulation  of  Work  ;  they  resemble  the  Effects  of  Exercises 
of  Strength — Effects  due  to  Expenditure  of  Nervous  Energy  ; 
resulting  Influence  on  Nutrition — Why  these  Exercises  cause 
Loss  of  Weight. 


We  call  those  exercises  which  need  the  very  frequent 
repetition  of  muscular  movement,  exercises  of  speed. 

There  are  great  differences  among  the  various 
exercises  of  speed  as  regards  the  intensity  of  work. 
Many  of  them  are  typical  violent  exercises  :  running, 
for  instance.  Many  on  the  contrary  need  so  insignificant 
an  expenditure  of  force  that  they  hardly  deserve  the 
name  of  exercise.  A  pianist  playing  scales,  notwith- 
standing the  extreme  speed  of  the  movements  of  his 
fingers,  performs  but  a  trifling  muscular  work. 

The  essential  character  of  exercises  of  speed  is  the 
rapid  multiplication  of  muscular  movements.  A  series 
of  inconsiderable  efforts,  often  repeated,  thus  allow  the 
performance  in  a  short  time  of  a  considerable  quantity 
of  work,  without  bringing  into  play  very  important 
muscular  masses.     In  fact  ten  movements  each  needing 


EXERCISES    OF    SPEED.  245 

an  expenditure  of  force  of  ten  kilogrammetres  must 
represent  the  same  work  as  one  movement  in  which  the 
expenditure  of  force  is  a  hundred  kilogrammetres,  and 
we  can  easily  understand  that  ten  rapid  movements  may 
be  performed  in  the  sam.e  time  as  one  very  slow  one. 
As  regards  the  quantity  of  work  done,  an  exercise  of 
speed  may  thus  be  absolutely  equivalent  to  an  exercise 
of  strength. 

Exercises  of  speed,  as  well  as  exercises  of  strength, 
may  then  produce  a  great  quantity  of  work  in  a  short 
space  of  time.  From  this  common  condition  are  derived 
certain  identical  effects,  breathlessness  for  instance. 
But  each  of  these  kinds  of  exercise  has  its  own  cha- 
racter, from  which  are  derived  very  different  results. 
The  one  kind  needs  that  the  muscles  should  contract 
with  all  the  energy  they  possess  ;  the  other  does  not 
need  this,  but  the  muscles  must  pass  at  very  short 
intervals,  and  a  great  number  of  times  in  succession, 
from  repose  into  action. 

The  essential  character  of  exercises  of  speed,  that  to 
which  their  very  remarkable  physiological  effects  are 
due,  is  this  frequently  repeated  change  of  the  muscles 
from  the  condition  of  relaxation  to  that  of  contraction. 

We  have  thus  to  study  exercises  of  speed  from  two 
very  different  points  of  view  :  (i)  the  rapidity  with  which 
the  work  accumulates,  (2)  the  speed  with  which  the 
movements  succeed  each  other. 

The  rapid  accumulation  of  work  depends  upon  two 
factors  which  are,  the  quantity  of  work  represented  by 
each  muscular  çffort,  and  the  number  of  these  efforts  in 
a  given  time.  Whether  the  work  accumulates  owing  to 
the  intensity  of  the  efforts  or  to  their  number,  the  results 
are  the  same.  Thus  the  breathlessness  will  be  the  same 
after  100  movements  each  representing  10  kilogram- 
metres,  as  after  10  movements  each  representing  lOO 
kilogrammetres,  if,  in  both  cases,  the  same  quantity  of 
work  has  been  done  in  the  same  time. — A  man  who 
slowly  goes  up  a  staircase  with  a  heavy  burthen  on  his 
shoulders  is  doing  a  work  of  strength.  A  man  running 
as  fast  as  he  can   along  a  level  road  is  performing  an 


246  PHYSIOLOGY    OF    BODILY    EXERCISE. 

exercise  of  speed.  Both  of  them  do  a  great  quantity  of 
work  in  a  very  short  time,  one  by  slow  movements 
each  representing  a  great  expenditure  of  force,  the 
other  by  rapid  movements,  each  of  which  taken  alone 
represents  a  very  much  smaller  quantity  of  work,  but 
which,  when  multiplied,  make  in  the  end  a  considerable 
expenditure  of  force. 

Thus  the  exercises  of  speed  can,  as  well  as  the  exer- 
cises of  strength,  lead  to  an  accumulation  of  work.  The 
man  who  runs  is  taking,  quite  as  much  as  the  man  who 
wrestles,  exercise  in  *'  large  doses." 

In  this  manner  speed  can  supplement  force,  and  enable 
certain  persons,  whose  muscular  development  is  feeble, 
to  benefit  from  the  general  effects  of  violent  exercise, 
without  needing  intense  efforts  which  they  would  be 
unable  to  perform.  The  intensity  of  the  combustions  of 
work  is  in  proportion  to  the  total  quantity  of  force  ex- 
pended, whether  this  expenditure  has  been  made  in  mass 
at  one  effort,  or  has  been  made  in  successive  fractions, 
by  little  efforts  at  very  short  intervals.  Now  the  forma- 
tion of  the  waste-products  of  combustion,  such  as 
carbonic  acid,  is  in  proportion  to  the  intensity  of  the 
combustion,  and  it  is  from  the  quantity  of  carbonic  acid 
accumulated  in  the  system  that  the  intensity  of  the 
respiratory  need  results,  and  from  this  the  amplitude 
and  frequency  of  the  respiratory  movements.  The  need 
of  absorbing  oxygen  is  intimately  connected  with  the 
need  for  the  elimination  of  carbonic  acid,  and  thirst  for 
air  is  the  inevitable  result  of  very  intense  muscular  work, 
be  its  mode  of  performance  strength  or  speed. 

Exercises  of  speed  produce,  quite  as  much  as  exercises 
of  strength,  this  thirst  for  air  which  is  to  respiration 
what  appetite  is  to  digestion.  Skipping,  running,  and 
the  numerous  children's  games  whose  essential  character 
consists  in  rivalry  of  speed  amongst  the  players,  are  as 
valuable,  and  more,  as  exercises  of  strength,  from  the 
point  of  view  of  respiratory  hygiene.  A  child  which  has 
just  been  playing  at  running  has  absorbed  without 
making  any  painful  muscular  effort,  in  simple  "  play," 
a  greater  quantity  of  oxygen   than  one  vrhich  has  been 


EXERCISES    OF    SPEED.  247 

made  to  use  heavy  dumb-bells.  Now  the  absorption  of 
the  greatest  possible  quantity  of  oxygen  seems  to  be,  on 
the  whole,  the  thing  most  desired,  when  we  need  the 
general  effects  of  exercise  with  a  hygienic  end  in  view. 

Among  the  Ancients,  the  exercises  of  speed  always 
held  the  first  rank.  Running  was  regarded  as  a  cri- 
terion of  athletic  superiority,  and  the  characteristic  of 
Achilles  in  Homer  was  the  quickness  of  his  legs. 

If  we  com.pare  exercises  of  strength  and  exercises  of 
speed  we  find  in  them  the  common  character  of  rendering 
respiration  more  active.  But  the  exercises  of  strength 
only  bring  about  this  result  at  the  price  of  intense 
muscular  fatigue,  while  exercises  of  speed  allow  the 
work  to  be  carried  on  till  breathlessness  is  produced 
without  the  muscles  becoming  painful  from  the  work. 
In  fact  four  successive  movements  each  representing  a 
force  of  ten  kilogrammetres,  do  not  submit  the  muscular 
fibres  to  as  severe  a  trial  as  a  single  movement  repre- 
senting forty  kilogramimetres.  It  may  happen  in  an 
exercise  of  strength,  that  the  intensity  of  the  contraction 
causes  in  the  organs  of  movement  a  strain  up  to  the 
very  limits  of  their  resistance,  sometimes  even  be3^ond, 
for  ruptures  of  tendons  and  aponeuroses,  and  even  frac- 
tures of  bones  are  frequent  accidents  in  exercises  of 
strength.  In  exercises  of  speed  the  muscle  does  not 
use  nearly  all  the  contractile  force  which  it  possesses, 
except  in  the  rare  cases  in  which  the  two  elements, 
strength  and  speed,  are  combined  to  form  forced 
exercise. 

Now  the  repetition,  even  if  very  frequent,  of  a  moderate 
muscular  contraction,  cannot  produce  in  the  organs  a 
strain  comparable  to  that  produced  by  contractions 
which  though  slow,  are  carried  to  the  utmiost  limits  of 
muscular  power.  To  be  convinced  of  this  it  is  enough 
to  perform  very  rapid  m^ovements  of  the  arm,  holding 
a  very  light  weight,  and  very  slow  movem.ents  holding 
a  very  heavy  vv^eight  :  it  will  be  apparent  that  the 
latter  proceeding  is  more  painful  than  the  former. 

Rapid  onset  of  breathlessness,  and  a  speedy  intoxica- 
tion of  the  system  by  carbonic  acici,  are  the  character- 


2.l8  PÎIYSIOLOGY    OF    BODILY    EXERCISE. 

istic  results  of  exercises  of  strength  when  they  are 
performed  with  some  speed.  The  rapid  repetition  of  a 
muscular  effort,  already  representing,  taken  alone,  a 
great  expenditure  of  force,  must,  we  can  easily  under- 
stand, produce  in  a  very  short  time  a  great  accumulation 
of  work,  by  multiplying  the  sum  of  the  kilogrammetres 
represented  by  each  effort  by  the  number  of  efforts 
which  take  place  in  a  given  time. 

Exercises  which  need  at  the  same  time  a  great  ex- 
penditure of  strength  and  a  great  speed,  may  be  called 
forced  exercises.  They  demand  more  work  from  the 
animal  machine  than  it  is  capable  of  performing  and 
must  only  be  continued  for  a  very  short  time,  under 
pain  of  causing  serious  accidents.  We  rarely  have  to 
observe  in  men  the  effects  of  this  excessive  accumula- 
tion of  work.  In  animals  we  often  see  examples, 
especially  in  the  horse,  that  noble  animal  which,  as 
Buffon  says,  "  dies  for  better  obedience."  An  eager 
horse  harnessed  to  a  heavy  cart,  and  made  to  gallop 
up  hill,  is  doing  at  once  a  work  of  strength  and  of 
speed,  and  often  gives  an  example  of  the  accidents  of 
forced  exercise  :  threatened  with  asphyxia  from  the 
accumulation  of  carbonic  acid  in  the  blood,  exposed 
to  ruptures  of  vessels,  or  to  visceral  lacerations  by  the 
violent  pressure  occasioned  by  the  effort,  the  animal 
sometimes  dies  suddenly  from  a  rupture  of  the  heart,  or 
falls  down  paralysed  by  a  haemorrhage  in  the  spinal  cord. 

Thus,  to  sum  up,  the  exercises  of  speed  have  the 
advantage  of  producing  the  same  quantity  of  work  as 
the  exercises  of  strength,  and  of  producing  the  same 
intensity  of  respiratory  need.  Further,  they  increase 
the  activity  of  the  respiratory  functions  with  less 
fatigue  of  the  lungs  and  heart,  owing  to  the  absence 
of  effort  which  only  exceptionally  occurs  in  exercises 
of  speed,  but  which  is  obligatory  in  exercises  of 
strength.  Hence  a  first  cause  for  preferring  exercises  of 
speed  when  the  object  is  to  increase  the  oxygenation 
of  the  patient. 

As  .  regards    the    muscular    system,   an   exercise   o^ 


EXERCISES    OF    SPEED.  249 

Speed,  for  an  equal  number  of  kilogrammetres  in  a 
given  time,  will  produce  less  fatigue  than  a  work  of 
strength,  and  will  subject  the  motor  apparatus  in  a 
less  degree  to  the  various  accidents  resulting  from 
shocks  and  frictions  of  its  constituent  parts. 

But  these  advantages  are  counterbalanced  by  another 
which  we  must  recognise  in  exercises  of  strength,  the 
greater  development  given  to  the  muscles.  The  flow  of 
blood  to  the  muscular  fibre  is  more  considerable  in  pro- 
portion to  the  intensity  of  the  effort,  and  more  prolonc^ed 
in  proportion  to  the  duration  of  the  contraction.  This 
fact  is  proved  by  the  following  observation.  In  a  man 
who  is  being  bled,  the  blood  runs  from  the  veins  for  a 
little  while  and  then  the  flow  stops.  If  we  then  cause 
him  to  move  the  muscles  of  his  forearm  the  flow  re- 
commxCnces,  not  because  the  veins  are  emptied  by 
increased  pressure,  but  because  the  contraction  draws 
more  blood  from  the  muscles.*  Now  if  the  muscles 
contract  in  an  energetic  and  sustained  manner  the  flow 
of  blood  is  rapid,  full,  and  uninterrupted.  If  we  cause 
the  patient  to  make  a  series  of  small,  rapidly  repeated 
contractions  of  the  muscles  of  his  forearm,  the  flow 
becomes  jerky,  small,  and  in  the  sam.e  period  of  time 
will  furnish  a  lesser  quantity.  This  experiment  proves 
that  less  blood  traverses  the  muscles  during  a  series  of 
small  contractions  frequently  repeated  than  during  one 
lono;  sustained  contraction. 

No  further  demonstration  is  needed  to  prove  that  the 
nutrition  of  muscle  must  be  less  active  during  exercises 
of  speed  than  during  exercises  of  strength,  for  we  know 
that  the  nutrition  of  a  region  of  the  body  is  active  in 
direct  proportion  to  the  quantity  of  blood  with  which  it 
is  supplied. 

The  deductions  we  have  just  made,  based  upon  the 
physiology  of  muscular  work,  are  fully  confirmed  by 
the  direct  observ^ations  of  facts.  The  exercises  of  speed 
do  not  sensibly  develop  the  muscles,  while  the  exercises 
of  strength  cause  a  great  increase  in  their  size.     Every 

•  Marey.     La  Circulation  du  Sang. 


250  PHYSIOLOGY    OF    BODILY    EXERCISE. 

one  knows  the  exaggerated  muscular  development  of 
the  strong  men  at  a  fair,  and  also  that  professional 
runners  often  have  small  calves.  On  the  other  hand 
the  exercises  of  speed  develop  more  than  others  the  size 
of  the  chest,  and  no  athletic  exercise  improves  the 
breathing  more  rapidly  than  long-distance  running. 

II. 

There  is  a  very  interesting  point  for  study  in  the 
physiology  of  the  exercises  of  speed  ;  this  is  the  ex- 
cessive expenditure  of  nervous  energy  which  they 
occasion.  Speed  in  the  movemxCnt  demands  an  increased 
work  from  the  nerve-centres  which  can,  we  believe,  be 
satisfactorily  explained  by  the  physiological  facts  we  are 
about  to  put  forward. 

A  muscle  never  obeys  instantaneously  the  will  which 
commands  a  movement.  This  fact  was  brought  to  light 
by  Helmholtz  in  1850.  This  physiologist  showed  that 
when,  by  means  of  an  electric  discharge,  a  given  point 
of  a  motor  nerve  is  stimulated,  an  appreciable  interval 
is  always  observed  between  the  moment  of  stimulation 
of  the  nerve  and  that  of  the  contraction  of  the  muscle. 
This  retardation  is  in  part  due  to  the  time  taken  by  the 
stimulus  in  travelling  along  the  nerve  ;  but,  taking  into 
account  the  duration  of  this  passage,  which  can  be  easily 
measured,  it  is  found  that  there  is  still  an  appreciable 
period  of  time  during  which  the  muscle  which  has 
already  been  stimulated  has  not  yet  begun  to  contract. 

Helmholtz  has  given  the  name  of  latent  -ùeriod  to 
the  silent  time  in  which  the  motor  organ,  having  already 
heard  the  call  of  the  will  has  not  yet  responded  by  a 
movement. 

Now  different  conditions  may  cause  variations 
in  the  length  of  the  latent  period,  and  make  the 
obedience  of  the  muscle  to  the  stimulus  it  receives  more 
prompt  or  the  reverse.  Among  these  conditions,  some 
are  inherent  in  the  muscle  and  may  be  summed  up 
under  one  head,  which  is  the  greater  or  less  irritability 
it  possesses  ;  the  others  depend  on  the  exciting  agent 
of  the  muscle,  and  are  in  subordination  to  the  greater 


EXERCISES    OF    SPEED.  2c;i 

or  less  intensity  with  which  this  agent  makes  its  action 
felt. 

The  most  efficient  condition  for  shortening  the  latent 
period  is  the  intensification  of  the  stimulus  received  by 
the  muscle.  If  we  suppose  a  motor  organ  to  be  set  in 
action  by  an  electric  current,  the  latent  period  being, 
for  instance,  two  hundredths  of  a  second,  with  an  electric 
force  we  will  call  i,  its  duration  will  be  reduced  to  one 
hundredth  of  a  second  if  we  double  the  intensity  of  the 
current.  Let  us  suppose  now  that  the  muscle  is  stimu- 
lated by  the  will  :  the  same  law  will  be  applicable  to 
the  duration  of  the  latent  period,  and  this  will  be 
shorter  in  proportion  as  the  order  of  the  will  is  accom- 
panied by  a  stronger  stimulation  of  the  muscular  fibre. 
Now  a  stronger  stimulation  of  the  muscular  fibre  can 
only  be  obtained,  as  we  said  in  the  first  part  of  this 
book,  at  the  expense  of  a  greater  disturbance  in  the 
cerebral  cells  and  the  nerve  fibres  which  are  the  con- 
ducting organs  of  the  voluntary  nervous  stimulus. 

The  effort  of  the  zvill, — a  synonym  for  the  nervous 
disturbance, — will  then  be  the  more  intense  the  shorter 
the  time  between  the  order  of  the  will  and  the  per- 
formance of  the  movement. 

Exercises  of  speed  which  demand  the  very  frequent 
repetition  of  movements,  that  is  to  say  the  very  rapid 
change  from  relaxation  to  contraction,  from  repose  to 
movement,  will  then  necessitate  a  supplementary  effort 
of  will  in  order  to  hasten  the  response  of  the  muscle 
to  the  call  made  upon  it.  Hence  there  is  an  increase 
of  nervous  expenditure  which  is  not  translated  by  a 
more  energetic  contraction,  but  by  a  more  speedy  one,  and 
which  does  not  lead  to  an  increase  of  the  work  done, 
but  to  a  diminution  of  the  latent  period. 

This  explanation,  which  we  believe  may  be  deduced 
from  the  law  of  Helmholtz,  is  confirmed  by  the  obser- 
vation of  facts,  for  exercises  of  speed  are  accompanied 
by  certain  phenomena  of  fatigue  out  of  proportion  to 
the  quantity  of  mechanical  work  they  represent,  and 
which  must  be  attributed  to  an  increase  of  the  nervous 
work. 


252  PHYSIOLOGY    OF    BODILY    EXERCISE. 

We  have  seen  that,  among  the  conditions  which  may 
cause  variation  in  the  latent  period,  we  must  take  into 
account  in  the  first  place  the  greater  or  less  ir)  itability 
of  the  muscle.  Irritability  is  the  property  possessed  by 
a  muscle  of  responding  by  a  contraction  to  a  stimulus 
which  it  receives  from  an  external  agent,  whether  this 
be  the  will,  or  some  other. 

There  are  causes  which  diminish  the  irritability  of 
muscle  ;  the  commonest  is  fatigue.  A  fatigued  muscle 
no  longer  responds  to  feeble  stimuli  which  were  at  the 
outset  sufficient  to  throw  it  into  activity.  Further,  if  the 
stimulus  becomes  stronger,  and  gains  sufficient  intensity 
to  provoke  a  contraction,  we  notic-e  that  this  contraction 
occurs  slowly,  and  that  the  latent  period  is  longer  than 
it  was  when  the  muscle  was  fresh.  To  obtain  a  vç-xy 
prompt  response  from  a  fatigued  muscle,  we  m.ust  have 
recourse  to  stimuli  of  very  great  intensity.  This  explains 
how  it  is  that  muscular  fatigue  makes  a  man  lose  his 
fitness  for  speed,  before  he  loses  the  power  of  making 
energetic  muscular  contractions. 

The  more  irritable  the  muscle,  the  more  ready  is  it  to 
obey  the  will  quickly,  the  more  capable  is  it  of  performing 
exercises  of  speed.  Now — and  this  is  a  point  worth 
noticing — all  the  muscles  have  not  naturally  the  same 
irritability  ;  all  have  not  the  same  aptness  for  responding 
quickly  to  a  stimulating  agent. 

In  certain  kinds  of  animals  we  notice  a  very  long 
interval  between  the  electric  stimulation  of  a  muscle  and 
its  contraction.  These  are  the  kinds  commonly  noted 
for  the  slowness  of  their  voluntary  movements.  It  is 
curious  to  see  the  muscle  of  a  tortoise,  for  instance,  not 
beginning  to  contract  for  two  hundredths  of  a  second 
after  stimulation,  while  in  the  muscle  of  a  bird  the  latent 
period  is  only  seven  thousandths  of  a  second.  This 
difference  is  still  more  striking  in  a  snail,  the  muscle  of 
which  does  not  begin  to  contract  till  three  tenths  of  a 
second  after  receiving  a  shock. 

When  we  have  frequented  a  gymnasium  and  have 
observed  many  men  performing  exercises,  we  have  been 
struck    by    noticing    the    different    irritability    of    the 


SXERCISES    OF    SPEED.  253 

muscles  in  différent  individuals.  In  some  persons 
rapidity  of  movement  is,  so  to  speak,  natural,  and  exer- 
cises of  speed  do  not  demand  any  great  effort  ;  their 
muscular  tissue  is  very  irritable.  In  other  persons,  on 
the  other  hand,  the  muscles,  although  energetic,  only  obey 
the  orders  of  the  will  with  considerable  slowness.  A 
great  expenditure  of  nervous  energy  is  necessary  to 
obtain  a  rapid  movement.  These  differences  are  often 
racial,  and  at  the  first  glance  are  seen  in  the  deportment. 
The  vivacious  step  of  the  Southron  contrasts  with  the 
calm  posture  of  the  man  of  the  North.  The  motor 
fibres  of  the  former  are  more  irritable  than  those  of  the 
latter.  It  is  curious  to  see  these  differences  manifesting 
themselves  in  physical  exercises,  and  to  ascertain  the 
difference  of  aptitudes  resulting  from  them  for  this  or 
that  form  of  work.  The  English  and  the  Germans 
have  never  been  able  to  rival  the  French  and  Italians 
in  fencing.  English  boxing  needs  above  all  massive 
strength  and  power  of  resistance  ;  French  boxing 
needs  on  the  contrary,  agility  and  readiness  in  the 
blows,  that  is,  great  suddenness  of  attack  and  quickness 
in  reply. 

A  boating  newspaper  reviewed  recently  the  different 
methods  of  rowing  prevalent  in  different  regions.  We 
were  struck  by  noticing  that  in  a  regatta,  the  French 
rowed  forty  strokes  a  minute,  the  Dutch  only  twenty-five. 

Speed  is  then  a  quality  of  work  which  depends  upon 
two  elements  ;  the  irritability  of  the  muscle  and  the 
strength  of  the  stimulus  which  it  receives. 

Engineers  passing  from  theoretical  to  applied 
mechanics  all  know  what  a  step  there  is  from  theory  to 
practice.  It  is  necessary  to  take  into  account,  for 
instance,  the  different  elasticity  of  the  various  materials 
employed,  their  greater  or  less  impressionability  to 
hygrométrie  or  thermic  influences.  In  a  w^ord,  each 
body  has,  besides  its  mass,  a  peculiar  physical  individu- 
ality which  modifies  the  conditions  under  which  it 
receives  the  influence  of  the  forces. 

Similarly  in  living  beings  we  must  take  into  account 
the  variations   in    muscular   irritability   if   we   wish   to 

18 


254  PHYSIOLOGY    OF    BODILY    EXERCISE. 

estimate  exactly  the  amount  of  force  expended  In  a, 
movement.  The  less  irritable  the  muscle,  the  greater 
must  be  the  expenditure  of  nervous  energy  the  object 
of  which  is  to  hasten  its  entry  into  action.  This  expen- 
diture of  force  is  not  appreciable  by  the  dynamometer  ; 
it  is  estimated  by  another  method  ;  by  the  time 
necessary  for  bringing  into  play  the  muscular  contrac- 
tility. This  expenditure  is  not,  in  reality,  borne  by  the 
muscle,  but  rather  by  the  agent  which  stimulates  it,  an 
agent  the  nature  of  which  is  still  obscure,  and  called, 
for  want  of  a  more  exact  word,  by  the  name  of  nervous 
e?tergy. 

From  the  very  active  intervention  of  the  nervous 
system  in  exercises  of  speed,  are  derived  certain  very 
important  hygienic  results. 

After  an  exercise  necessitating  the  very  frequent 
repetition  of  movements,  the  fatigue  experienced  is  more 
painful  than  that  which  results  from  a  more  intense 
work,  but  is  performed  by  the  aid  of  slow  movements. 
The  fatigue  which  follows  an  exercise  of  speed  is  unlike 
that  experienced  after  an  exercise  of  strength.  Under 
the  influence  of  a  muscular  contraction  which  is  intense, 
but  slow  and  prolonged,  the  fatigue  is  felt  especially  by 
the  muscle.  The  limbs  are  weary,- they  are  also  con- 
gested ;  the  blood  flows  to  them  and  swells  them  up. 
This  is  because  the  muscular  fibres  have  been  the 
essential  agents  of,  and  almost  the  only  factors  in,  the 
work.  After  movements  representing  a  small  expendi- 
ture of  force,  but  performed  with  very  great  speed,  we 
experience  a  fatigue  which  recalls  the  sensation  of  a 
nervous  disturbance  of  a  moral  order. 

In  place  of  this  lassitude  which  is  an  open  invitation 
to  repose,  and  which  is  a  really  pleasant  condition  after 
a  great  quantity  of  work  quickly  performed,  there  is  felt, 
after  an  exercise  of  speed,  a  kind  of  exhaustion  accom- 
panied by  nervous  excitability  ;  a  feeling  of  enervation 
is  experienced,  which  may  either  be  characterised  by 
prostration,  or  by  excitability,  or  even  by  undue 
sensitiveness.  The  expression  "  nervous  fatigue  "  gives 
a    good    idea   of   this    kind  of    disturbance  which  will 


EXERCISES    OF    SPEED.  255 

easily  be  rccof^nised  by  those  who  have  ever  immode- 
rately  prolonged  an  exercise  of  speed.  We  may  say  in 
a  general  sense  that  the  fatigue  left  by  exercises  of  speed 
is  not  reparatory.  It  invites  less  plainly  to  sleep,  and 
excites  the  appetite  less  than  the  fatigue  resulting  from 
a  slow  expenditure  of  force. 

The  great  expenditure  of  nervous  energy  which  the 
exercises  of  speed  render  necessary  is  certainly  the 
cause  which  makes  the  repair  of  the  system  after  these 
exercises  more  difficult.  We  know  the  important  office 
of  the  nervous  system  in  nutrition,  and  the  rapid 
atrophy  which  regions  of  the  body  undergo  when  the 
distribution  of  nervous  energy  is  hindered,  whether  by 
section  of  the  nerves  or  by  a  paralysis  of  central  origin. 

It  is  then  no  doubt  to  the  considerable  expenditure 
of  nervous  energy  and  to  the  inevitable  prostration 
which  follows  it,  that  we  must  attribute  the  loss  of 
weight  observed  in  exercises  of  speed.  We  observe 
this  tendency  to  malnutrition  in  all  circumstances  of  a 
physical  or  moral  order  which  call  forth  a  great  expen- 
diture of  nervous  energy.  A  man  rapidly  becomes  thin 
under  the  influence  of  continual  mental  distress,  or  very 
sustained  intellectual  work. 

We  believe  that  if  an  exercise  of  speed  causes  loss  of 
weight,  it  is  not  so  much  due  to  the  excessive  expendi- 
ture which  accompanies  it,  as  to  the  defective  repair 
which  follows  it.  Hence,  from  the  excessive  expenditure 
of  nervous  energy  which  occurs  in  order  to  hasten  the 
muscular  contraction,  there  results  a  temporary  ex- 
haustion of  the  forces  which  preside  over  nutrition,  and 
the  tissues  burned  in  the  work  have  no  tendency  to 
repair. 

There  occurs  during  an  exercise  of  speed  a  nervous 
commotion  resembling  that  which  follows  a  strong 
emotion  or  a  powerful  mental  strain.  The  fatigue  due 
to  speed  often  prevents  appetite  and  sleep.  These 
results  are  especially  marked  in  impressionable  persons, 
and  it  is  among  them  that  we  may  see  how  fatigue 
caused  by  speed  is  adverse  to  the  repair  of  the  system. 
Many   children,   after    running    about    too   much,    can 


256  PHYSIOLOGY    OF    BODILY    EXERCISE. 

neither  eat  nor  sleep.  Many  horses  which  are  too 
nervous  refuse  their  oats  after  a  hard  day's  huntinj^. 
We  do  not  see  this  capricious  appetite  in  coarsely  built 
animals  which  do  collar-work  all  day. 

In  man  it  is  remarkable  to  note  the  different  effects 
on  nutrition  of  exercises  of  speed  and  of  exercises  of 
strength.  Navvies,  porters,  strong  men  at  a  fair,  have 
usually  a  massive  build  which  becom.es  more  and  more 
marked  by  the  exercise  of  their  profession.  Runners, 
dancers,  fencing-masters,  are  generally  slender  and  thin. 

If  we  wish  to  sum  up  in  a  few  words  the  effects  of 
exercises  of  speed,  we  see  that  we  must  distinguish 
between  the  effects  due  to  the  accumulation  of  work, 
and  those  due  to  the  frequency  of  movements. 

Exercise  of  speed  has  one  point  in  common  with 
exercise  of  strength  ;  this  is  the  great  quantity  of 
mechanical  work  which  it  can  produce.  The  rapid 
succession  of  a  great  number  of  efforts,  leads,  in 
ultimate  analysis,  to  the  same  results  as  the  great 
intensity  of  a  small  number  of  efforts  at  longer 
intervals.  We  may  say,  to  borrow  an  idea  from 
therapeutics,  that  these  two  modes  of  exercise  have 
for  result  the  habituation  of  the  system  to  "large 
doses"  of  work. 

But  exercises  of  speed  have  special  results  very 
different  from  those  of  exercises  of  strength.  These 
results  are  not  due  to  the  great  quantity  of  mechanical 
work  done,  but  to  the  rapid  succession  of  the  move- 
ments. The  speed  of  movements  has  on  the  system  a 
peculiar  influence,  independent  of  their  greater  or  less 
energy.  It  is  by  the  nervous  system  that  this  influence 
is  felt,  and  it  is,  in  ultimate  analysis,  to  an  increased 
work  of  the  nerve-centres  that  the  very  specialised 
effects  of  exercises  of  speed  are  due. 


CHAPTER  V. 

EXERCISES   OF    ENDURANCE. 

Conditions  of  Exercise  of  Endarance  ;  Moderation  of  Efforts  ; 
Slow  Repetition — Fractional  Work— Conditions  Inherent  in  the 
Worker.  Men  and  Animals  who  have  "  Staying  Power  " — Need 
for  perfect  Equilibrium  between  the  Intensity  of  the  Work  and 
the  Power  of  Resistance  of  the  System — Importance  of  Respira- 
tion in  regulating  Exercise  of  Endurance  —  Exercise  of 
Endurance  makes  the  Functions  more  Active  without  Fatiguing 
the  Organs — Association  of  the  Great  Functions  with  Moderate 
and  Prolonged  Muscular  Work  ;  Respiration  more  Active 
without  Breathlessness;  Circulation  Quickened  without  Palpita- 
tion —  Indications  and  Contra-indications  for  Exercises  of 
Endurance— Parallel  with  Exercises  of  Speed — Why  Children 
bear  Exercises  of  Endurance  badly — Veterans  and  Conscripts. 

I. 

We  call  exercises  of  endurance  those  in  which  the  work 
must  be  continued  for  a  long  time. 

In  these  exercises  the  expenditure  of  force  is  deter- 
mined less  by  the  intensity  and  rapid  succession  of 
efforts,  than  by  their  duration.  It  is  necessary  that  the 
muscular  effort  shall  not  be  too  considerable,  and  the 
movements  not  too  rapid,  in  order  that  fatigue  under 
its  various  forms  may  not  interrupt  them  too  soon.  So 
that  an  exercise  of  endurance  is  only  moderate  exercise 
if  it  lasts  a  short  time,  while  it  may  become  forced 
exercise  if  it  be  continued  too  long. 

In  these  exercises  the  quantity  of  work  done  after  a 
long  time,  at  the  end  of  a  day,  for  instance,  may  be 
very  considerable,  but  the  expenditure  of  force  is  made 
in  such  smiall  fractions  that  there  is  no  painful  muscular 
effort,  nor  any  marked  disturbance  in  the  organic 
functions.  So  that  a  man  performing  an  exercise  of 
endurance  may  pass,  almost  without  noticing  it,  to 
strong  doses  of  muscular  work. 


258  PHYSIOLOGY    OF    BODILY    EXERCISE. 

The  animal  machine  is  made  in  such  a  manner  as  to 
be  able  to  perform  without  fatigue  movements  of  a 
determined  intensity  and  speed.  When  these  limits  are 
not  exceeded,  no  appreciable  disturbance  is  produced  in 
the  system,  and  the  work  is  done  amidst  complete 
tranquillity  of  the  vita'  functions.  Thanks  to  the  perfect 
equilibrium  between  the  muscular  exertion  and  the 
power  of  resistance  of  the  subject,  he  is  able  in 
exercises  of  endurance  to  go  on  working  for  a  long 
time,  and  let  the  useful  effects  of  work  insensibly 
accumulate,  without  causing  any  disturbance  to  the 
various  parts  concerned  in  its  performance. 

We  see  at  once  the  importance  and  usefulness  of 
exercises  of  endurance  when  we  have  to  do  with  a  feeble 
system,  with  a  person  of  low  resisting  power,  to  whom 
we  wish  to  give  the  benefits  of  muscular  work,  while 
enabling  him  to  avoid  the  dangers  of  fatigue.  Similarly 
we  are  sometimes  able  to  give  a  sick  man  a  very 
energetic  remedy  by  administering  it  to  him  in  "  frac- 
tional doses." 

The  division  of  work  into  fractional  quantities 
sufficiently  small  to  enable  the  system  to  support  each 
one  without  disturbing  its  normal  functions,  such  is  the 
essential  condition  of  exercises  of  endurance. 

Another  condition  is  necessary  to  constitute  an 
exercise  of  endurance  ;  the  muscular  efforts  must  be  at 
intervals  sufficiently  long  that  the  effect  of  a  second 
may  not  be  added  to  that  of  a  first.  Between  two 
successive  doses  of  work  there  must  be  a  sufficient  time 
for  repose. 

There  are  organs  in  the  human  body  which  perform 
a  considerable  work  continuously  throughout  life.  It  is 
surprising,  for  instance,  to  think  how  the  hollow  muscle 
we  call  the  heart,  goes  on  contracting  from  birth  till 
death,  without  ever  suspending  or  slackening  its  work. 
This  is  because  the  cardiac  muscle  performs  a  work  of 
endurance.  The  expenditure  of  force  at  each  beat  is 
well  balanced  with  the  power  of  resistance  of  the  system 
of  which  it  forms  a  part,  and  the  interval  between  two 
beats    is    a   time   just    long   enough  to  rest  the   fibres. 


EXERCISES    OF    ENDURANCE.  259 

But  if  some  circumstance  occurs  which  increases  the 
work  of  the  org-an,  as  wc  see  in  constriction  of  the 
orifices  for  instance,  or  if  the  contractions  become  im- 
moderately frequent,  as  is  the  case  in  palpitation,  the 
conditions  of  work  are  changed.  The  heart,  instead 
of  having  to  do  a  simple  work  of  endurance,  has  to 
do  a  work  of  speed  or  strength  incompatible  with 
continued  work  ;  the  muscle  becomes  fatigued,  its  fibres 
lose  their  elasticity  and  their  energy,  there  is  overwork 
of  the  heart,  and  a  condition  of  asystole  comes  on,  of 
which  death  is  the  inevitable  consequence. 

Similarly  in  the  muscles  of  animal  life,  increased 
energy,  or  more  rapid  succession  of  movements,  tends  to 
make  the  exercise  of  endurance  pass  into  one  of  speed  or 
of  strength. 

In  an  exercise  of  strength  there  is  accumulation  of  work, 
because  each  muscular  eftbrt  is  very  intense.  In  an 
exercise  of  speed  there  is  multiplication  of  work,  for  the 
movements  have  little  energy,  but  the  rapid  succession  of 
efforts  of  small  intensity  leads  in  the  end  to  an  accumula- 
tion of  work.  In  an  exercise  of  endurance,  on  the  contrary, 
the  efforts  being  repeated  at  sufficient  intervals,  the  work 
is  fractional^  for  at  any  moment  the  quantity  of  work 
performed  by  the  organism  does  not  exceed  its  power  of 
resistance. 

Among  exercises  ordinarily  practised,  which  are  those 
we  may  call  exercise  of  endurance  ?  This  question  raises 
a  first  difficulty,  for  the  same  exercise  may  represent  in 
turn  a  work  of  speed,  a  work  of  strength,  or  a  work  of 
endurance,  according  to  the  conditions  in  which  it  is 
performed. 

Rowing,  for  example,  is  a  work  of  speed  in  a  rowing- 
match,  and  a  work  of  endurance  in  a  long  course.  Walking, 
which  is  the  type  of  exercises  of  endurance,  may  present 
the  characters  of  an  exercise  of  strength  when  it  is  per- 
formed on  a  very  steep  slope.  Thus  in  certain  ascents  in 
which  it  is  necessary  to  climb  almost  perpendicular  slopes, 
each  step  represents  a  great  expenditure  of  muscular 
force,  and  the  tourist  is  obliged  to  interrupt  his  work  as 


260  PPIYSÎOLOGY    OF    BODILY    EXERCISE. 

frequently  as  if  he  were  walking    in    the  plain  with  a 
heavy  burthen  on  his  shoulders. 

The  conditions  under  which  the  man  performing  the  ex- 
ercise is  placed  have  no  less  importance  than  the  exercise 
itself  in  determining  its  character  as  one  of  endurance. 

Exercise  of  endurance  is  characterised  by  the  necessity 
for  perfect  equilibrium  between  the  intensity  of  muscular 
effort  and  the  power  of  resistance  of  the  system.  Now 
there  is  nothing  so  variable  as  the  power  of  resistance  of 
each  individual.  So  that  which  is  for  one  man  an 
exercise  of  strength  or  of  speed,  becomes  for  another, 
stronger  or  better  trained,  a  simple  exercise  of  endurance. 
A  canter  is  an  exercise  of  speed  for  a  cart  horse,  used 
only  to  walk  ;  it  is  an  exercise  of  endurance  for  a 
thoroughbred,  which  can  sustain  this  pace  for  an  entire 
day  without  stopping.  Rowing  seems  an  exercise  of 
strength  to  a  man  who  is  learning  ;  after  a  quarter  of  an 
hour  he  is  out  of  breath.  For  a  waterman  it  is  an 
exercise  which  he  can  perhaps  keep  up  a  whole  day 
without  any  fatigue. 

There  are  then  two  conditions  necessary  to  constitute 
an  exercise  of  endurance  :  (i)  a  certain  moderation  in 
the  violence  of  the  exercise,  (2)  a  certain  power  of  resist- 
ance on  the  part  of  the  system. 

This  is  why  the  word  "  staying-power,"  which  conveys 
the  idea  of  length  of  time,  applies  rather  to  the  qualities 
of  the  man  or  the  animal,  than  to  the  nature  of  the  work 
they  perform.  A  work  of  endurance  is  one  whose  mode 
of  performance  enables  it  to  be  long  continued  ;  and  a 
man  or  animal  with  "  staying  power  "  are  those  whose 
system  is  fit  to  support  prolonged  work. 

Certain  persons  are  unable  to  perform  the  most 
moderate  exercise  without  showing,  after  a  very  short 
time,  the  signs  of  extreme  fatigue.  There  are  others 
who  keep  up  with  surprising  power  of  resistance  the 
most  violent  exercises,  and  for  them  exercises  of 
strength  and  of  speed  become  exercises  of  endurance. 

Generally  these  differences  in  power  of  resistance, 
in  the  staying  power  of  different  people,  are  due  to 
differencea  in  their  respiratory  powers. 


EXERCISES    OF    ENDURANCE.  26r 

We  may  say  that  the  respiratory  fitness  of  the 
individual  is  the  true  [regulator  of  a  work  of  en- 
durance. 

In  order  that  an  exercise  may  be  long  continued 
the  first  condition  is  that  it  does  not  lead  to  breath- 
lessness.  We  can  go  on  walking  in  spite  of  weary 
legs  and  sore  feet  ;  but  we  cannot  go  on  running 
when  we  are  out  of  breath.  We  saw  in  the  chapter  on 
Breathlessness  that  this  form  of  fatigue  is  due  to  an 
intoxication  of  the  blood  by  an  excess  of  carbonic  acid. 
To  escape  from  this  intoxication,  which  renders  the  con- 
tinuance of  the  work  impossible,  a  man  must  eliminate 
the  excess  of  carbonic  acid  as  fast  as  it  is  formed,  and, 
the  formation  of  carbonic  acid  being  in  proportion  to 
the  quantity  of  work  done  in  a  given  time,  we  may 
definitely  conclude  that  in  an  exercise  of  endurance,  the 
work  of  the  muscles  must  be  subordinated  to  the  power 
of  the  lungs.  Thus  all  the  conditions  which  increase 
the  respiratory  power  increase  the  fitness  for  keeping  up 
intense  work  for  a  long  time,  and  a  man  has  "  staying 
power  "  when  he  has  "  wind." 

II. 

The  effects  of  exercise  of  endurance  may  be  exactly 
deduced  from  the  conditions  in  which  this  exercise  is 
performed.  Evidently  an  exercise  which  is  incompatible 
with  breathlessness  will  lead  to  none  of  the  accidents  of 
forced  respiration.  During  such  an  exercise  there  will 
be  no  fear  of  rupture  of  tendons,  of  laceration,  or  of 
excessive  shaking  of  muscular  fibres,  for  the  movements 
must  never  become  so  violent  as  to  exceed  the  power  of 
resistance  of  the  organs.  Further,  exercise  of  endurance 
does  not  sensibly  disturb  the  working  of  the  organs, 
hence  in  it  there  will  be  no  very  energetic  association  of 
the  great  functions  of  the  economy  with  the  muscular 
work.  In  a  man  walking,  for  instance,  there  will  not  be 
the  rapid  rise  of  temperature,  the  copious  perspiration, 
the  excessive  quickening  of  the  pulse  and  the  violent 
panting  which  we  observe  in  a  runner. 

Still  we  must  not  imagine  that  even  the  most  moderate 


262  PHYSIOLOGY    OF    BODILY    EXERCISE. 

exercises,  when  long  continued,  can  be  compatible  with 
the  maintenance  of  the  functions  in  an  absolutely  calm 
and  normal  condition.  The  most  moderate  and  most 
localised  muscular  contraction  will  in  the  end  bring  about 
an  association  of  the  great  functions  of  the  economy  in 
the  work.  We  have  already  quoted  the  curious  ex- 
periment of  Chauveau,  proving  that  the  work  of  mas- 
tication, as  moderate  and  localised  as  work  can  be,  can 
influence  the  general  circulation  of  the  blood.  In  a  horse 
moving  its  jaws  in  chewing  oats,  we  can  ascertain  that 
the  blood-current  is  sensibly  quickened  in  the  muscles 
of  mastication.  A  more  energetic  call  for  nutrient  fluid 
is  made  by  the  fibre  at  work.  For  some  minutes  the 
quickening  is  confined  to  the  blood  vessels  supplying 
the  muscles  in  action  ;  but  soon,  if  the  chewing  move- 
ments go  on,  the  quickening  movement  gradually 
spreads,  and  involves  the  heart  itself,  so  that  the 
number  of  pulsations  is  increased  through  the  whole 
extent  of  the  circulatory  system. 

Such  is  the  influence  of  the  duration  of  a  muscular 
action.  A  work  which  is  local  and  insignificant,  if 
prolonged  a  certain  time,  comes  in  the  end  to  make 
its  effects  felt  on  the  general  system  by  associating  in  the 
work  of  the  muscles  the  most  important  of  the  great 
functions  of  the  economy,  the  circulation  of  the  blood. 

But  the  blood-current  cannot  be  quickened  without 
the  other  functions  being  associated  in  the  increased 
activity.  The  blood,  by  the  very  fact  of  its  more 
rapid  movement,  rises  in  temperature  from  increased 
friction  against  the  vessel-walls.  The  nerve-centres 
receiving  more  blood  and  hotter  blood  must  be  excited 
to  a  degree  ;  and  the  lungs  are  also  subjected  to  two 
influences  capable  of  making  them  more  active  ;  on 
the  one  hand,  the  blood  passing  through  their  capil- 
laries is  increased  in  quantity  and  needs,  for  its  aeration, 
a  greater  quantity  of  oxygen  ;  hence  increase  of  the 
respiratory  need  and  quickening  of  the  respiratory 
movements;  on  the  other  hand,  the  warming  of  tie 
blood  tends  to  make  the  respiration  more  active,  for 
heat  stimulates  the  respiratory  movcm^ents. 


EXERCISES    OF'    ENDURANCE.  263 

We  see  how  the  duration  of  work,  an  essential  cha- 
racter of  exercises  of  endurance,  forces  the  whole 
system  to  associate  by  a  greater  activity  of  all  its 
functions,  in  muscular  actions  the  effects  of  which  at 
first  sight  appear  to  be  localised  in  particular  portions  of 
the  body. 

This  association  of  the  great  functions  in  the  work,  or, 
in  other  words,  the  general  effects  of  the  exercise,  are 
never  as  considerable  in  exercises  of  endurance  as  in 
exercises  of  speed  or  of  strength.  We  do  not  observe, 
for  instance,  in  the  foot-soldier  making  a  long  march, 
these  violent  movements  of  the  respiratory  apparatus 
and  the  palpitation  of  the  heart  which  are  inevitable 
in  the  runner.  Further,  owing  to  the  moderate  nature 
of  the  work  there  is  no  need  during  the  exercise  to 
bring  into  action  all  possible  force,  and  to  make  an 
effort.  The  absence  of  effort  saves  a  man  performing 
such  exercise  from  the  violent  compression  of  the 
heart  and  great  vessels  which  hinders  the  working  of 
these  organs  and  makes  their  sustained  function  im- 
possible. 

The  physiological  effect  of  exercise  of  endurance  is,  to 
spare  the  organs  while  increasing  in  a  salutary  degree  the 
play  of  their  functions.  Its  most  essential  character  is  to 
give  to  the  system  a  power  of  repairing,  even  during 
the  work,  the  greater  number  of  the  disturbances 
which  occur  in  the  machine.  Thus  breathlessness  does 
not  occur  during  exercises  of  endurance  ;  the  quantity 
of  carbonic  acid  produced  by  the  muscles  never  rises 
to  a  quantity  in  excess  of  that  which  the  lungs  can 
eliminate,  it  is  removed  from  the  blood  as  fast  as  it 
is  formed,  and  passes  unnoticed  from  the  system. 

To  this  immunity  from  breathlessness  there  is  added 
in  exercises  of  endurance,  a  considerable  introduction 
of  oxygen  into  the  system.  If  we  refer  to  the  table 
of  Dr.  Edward  Smith,*  we  find  the  following  are  the 
comparative  effects  of  the  different  modes  of  exertion 
on  the  quantity  of  air  which  is  introduced  into  the  lungs  : 
«  Health  and  Disease,  p.  300. 


264  PHYSIOLOGY    OF    BODILY    EXERCISE. 

The  state  of  rest  in  the  lying  posture  is  regarded  as 
unity. 

Thus  the  effect  in  the  lying  posture  being        i.o 
That  of  the  sitting  posture  is         ...         ...       1.18 

The  standing  posture         ...  ...  ...       1.33 

Walking  at  2  miles  per  hour         ...         ...       2.76 

Running  at  6  miles  per  hour         ...  ...       7.0 

According  to  this  table  the  amount  of  air  consumed 
by  a  man  sitting  being  1.18,  that  of  a  man  walking 
exceeds  it  by  1.58,  and  that  of  a  man  running  exceeds 
it  by  5.91. 

Thus  a  man  walking  receives  every  minute  the  benefit 
of  an  excess  of  oxygen  represented  by  1.58,  and  a  man 
running  of  an  excess  represented  by  5.91.  If  we 
compare  these  two  numbers  we  see  that  their  ratio  is 
nearly  as  4  to  i  ;  but  from  this  little  calculation  we 
get  a  somewhat  unexpected  result  that  a  man  who 
has  walked  for  four  hours  has  passed  as  much  oxygen 
through  his  lungs  as  a  man  who  has  run  for  one  hour. 

In  other  words,  let  us  suppose — a  thing  much  open 
to  dispute — that  the  air  introduced  into  the  lungs  is 
as  well  assimilated  during  running  as  during  walking, 
it  will  be  enough  to  walk  for  an  hour  to  benefit  from 
the  same  excess,  from  the  same  gain  of  oxygen  as  if 
we  had  run  for  a  quarter  of  an  hour.  It  is  easier  to 
walk  for  an  hour  than  to  run  for  a  quarter  of  an 
hour,  and  the  gain  being  equal  from  the  point  of 
view  of  the  oxygen  acquired,  it  would  seem  that 
walking  is  always  to  be  preferred  to  running,  and 
that,  in  general,  the  exercises  of  endurance  are  worth 
more  than  the  exercises  of  speed.  They  are  in  fact 
preferable  in  all  cases  in  which  we  have  to  do  with 
persons  whose  lungs  or  heart  are  in  a  condition  to 
cause  anxiety  to  the  doctor,  and  whose  blood  needs 
to  be  enriched  by  an  increase  of  oxygen.  They  v»{ll 
make  this  gain  on  better  terms. 

On  the  other  hand,  the  exercises  of  endurance, 
always  leaving  the  working  of  the  lungs  comparatively 
tranquil,  do  not  demand  the  great  inspiratory  efforts 
which    force    all    the    air-cells    to    open    out.     In    the 


EXERCISES    OF    ENDURANCE.  2(55 

state  of  repose  there  is  always  a  great  number  of 
air-cells  remaining  inactive  ;  their  walls  are  flaccid 
and  collapsed,  there  are  whole  regions  of  the  lung 
which  take  no  part  in  the  respiratory  act.  When  the 
lungs  bring  their  whole  respiratory  force  into  play, 
no  region  remains  inactive,  and  the  most  remote  air- 
cells  are  opened  up.  The  lungs  become  as  large  as 
possible,  and  push  out  the  walls  of  the  thorax.  Hera  is 
the  most  precious  effect  of  the  exercises  which  cause 
breathlessness.  They  tend  to  increase  the  capacity  of 
the  chest.  Now  the  exercises  of  endurance  do  not 
lead  to  breathlessness. 

The  exercises  of  endurance  render  more  active  the 
gaseous  interchange  and  enrich  the  blood  with  a 
greater  quantity  of  oxygen,  but  their  effect  ceases 
there  :  they  do  not  excite  with  sufficient  violence  the 
respiratory  movements  to  modify  the  shape  of  the 
chest.  They  have  their  indications  and  their  advan- 
tages ;  they  also  fall  short  in  some  directions.  The 
doctor  must  weigh  the  pros  and  the  cons,  and  must 
deduce  from  examination  of  his  patient  the  formal 
indication  for  one  exercise  rather  than  another. 

Those  whose  lungs  are  suspect,  for  whom  violent 
respiratory  movements  would  present  dangers  ;  those 
also  whose  heart  is  not  in  a  state  of  perfect  integrity, 
or  in  whom  we  suspect  arterial  degeneration  which 
diminishes  the  strength  of  the  vessels  ;  all  those,  in 
short,  whose  organs  of  respiration  and  circulation 
present  a  certain  fragility,  should  prefer  exercises  of 
endurance  to  exercises  of  strength  or  of  speed. 

III. 

Aged  men,  persons  suffering  from  gouty  or  alco 
holic  vascular  degeneration,  persons  suffering  from  fatty 
infiltration  of  the  heart,  should  confine  themselves 
exclusively  to  exercise  of  endurance. 

Patients  who  very  easily  lose  breath,  emphysematous 
persons  for  instance,  cannot  perform  any  exercise  of 
speed  or  of  strength,  and  the  same  is  the  case  with 
phthisical    persons.     But    still    patients    of   both    these 


266  PHYSIOLOGY    OF    BODILY    EXERCISE. 

classes  have  need  of  supplementary  respirations  to 
compensate  for  the  insufficiency  of  the  respiratory 
field  which  has  been  reduced  by  the  disease,  some- 
times by  as  much  as  half.  Exercises  of  endurance 
constitute  in  such  cases  a  valuable  means  of  treatment. 
They  make  it  possible,  through  increasing  by  a  very 
little  at  a  time  the  carbonic  acid  formed  by  work, 
that  the  whole  of  this  excess  shall  be  eliminated  at 
each  expiration,  there  being  in  exchange  a  small 
excess  of  oxygen  introduced  during  inspiration.  If 
the  exercise  is  well  regulated  it  can  be  kept  up  for 
hours,  and  the  patient  will  then  have  benefited  with- 
out incurring  the  dangers  of  breathlessness,  from  a 
series  of  small  quantities  of  oxygen  the  sum  total  of 
which  will  be  equal  to  that  gained  by  a  healthy  man 
in  an  exercise  of  strength  or  of  speed.  Referring  to 
the  calculation  made  above,  we  see  that  moderate 
exercise,  like  walking,  kept  up  for  four  hours,  makes 
a  man  absorb  as  much  supplemental  oxygen  as  a 
most  violent  exercise,  such  as  running,  does  in  an 
hour. 

Generally  we  do  not  make  use  enough  of  exercises  of 
endurance  in  treating  patients  with  lung  trouble.  We 
should  boldly  prescribe  for  tubercular  or  asthmatic 
patients  long  walks  on  level  ground,  or  sustained 
exercise  at  the  oar,  coming  down  stream  and  rowing 
with  a  very  slow  stroke. 

Respiration  is  the  most  important  of  the  functions 
înfluenced  by  exercise,  but  it  is  not  the  only  one  to  be 
considered  in  exercises  of  endurance.  The  respiratory 
function  is  for  the  elimination  of  carbonic  acid  and  of 
many  other  substances  resulting  from  the  combustions 
of  work,  but  all  the  products  of  combustion  are  not 
eliminated  by  the  lungs. 

The  fractional  performance  of  work,  which  lends  itself 
so  well  to  the  regular  expulsion  of  carbonic  acid,  has 
not  the  same  influence  on  the  elimination  of  the  other 
products  of  dissimilation,  on  the  waste-products  found 
in  the  urir.e  for  instance.     If  we  refer  to  the  chapter 


EXERCISES    OF    ENDURANCE.  267 

dealing  with  the  urinary  deposits  which  occur  after 
work,  we  shall  easily  understand  that  the  fractional  per- 
formance of  the  work  cannot  hinder  the  accumul;ition 
of  the  products  of  combustion  which  are  eliminated  by 
the  urine,  because  this  elimination  is  a  slow  process. 
The  carbonic  acid  formed  during  work  is  immediately 
eliminated  by  the  lungs  ;  the  sparingly  soluble  com- 
pounds resulting  from  muscular  waste  are  not  found  in 
the  urine  for  at  least  three  hours  after  the  muscular 
work  which  has  led  to  their  production.  If  the  slowness 
of  the  work  can  retard  the  time  when  these  waste- 
products  will  accumulate,  their  accumulation  is  none  the 
less  inevitable,  for  in  an  exercise  which  has  lasted  three 
hours,  the  work  will  be  finished  before  the  system  has 
got  rid  of  any  particle  of  these  waste-products. 

This  is  why  an  exercise  of  endurance,  if  it  may  retard 
the  onset  of  fatigue,  cannot  save  the  system  from  its 
consequences. 

Here  is,  moreover,  a  remarkable  confirmation  of  our 
theory  of  stiffness.  We  believe  that  the  stiffness  of 
fatigue  is  due  to  an  overcharge  of  the  blood  with  urates, 
a  kind  of  transient'  uricœniia^  just  as  breathlessness, 
another  form  of  fatigue,  is  due  to  the  presence  of  an  ex- 
cessive quantity  of  carbonic  acid  in  the  blood.  A  man 
who,  not  being  in  training,  goes  out  for  a  day's  shooting, 
will  inevitably  suffer  on  the  following  day  from  a  more 
or  less  severe  attack  of  stiffness,  and  yet  his  exercise^ 
the  type  of  an  exercise  of  endurance,  will  not  have  pro- 
duced breathlessness  at  any  time  during  the  day. 

These  observations  give  us  the  key  to  a  fact  which  is 
at  first  sight  very  surprising,  and  even  inexplicable  except 
on  our  theory,  namely  that  young  persons  support  better 
exercises  of  speed  than  exercises  of  endurance. 

A  child  of  seven  years  old  will  bear  very  well  all  the 
games  which  need  rapid  and  prolonged  running.  This 
is  owing  to  the  wonderful  ease  with  which  its  lungs 
adapt  themselves  to  the  exigences  of  forced  respiration. 
The  carbonic  acid  produced  by  work  is  eliminated  with 
great  rapidity  and  causes  no  inconvenience  to  the  system. 


268  PHYSIOLOGY    OF    BODILY    EXERCISE. 

'  But  carbonic  acid  is  not  the  only  product  of  disfimila- 
lion  due  to  work  which  must  be  eliminated  from  the 
system,  and  there  are  others  whose  exit  is  slower,  notably 
those  resulting  from  the  dissimilation  of  the  nitrogenous 
tissues.  Now  dissimilation  is  inucJi  more  rapid  in  the 
child  than  in  the  adult,  for  the  young  tissues  have  less 
stability  than  the  adult  tissues.  Hence  the  formation  of 
nitrogenous  waste-products,  of  which  uric  acid  and  urates 
are  the  chief,  is  more  abundant.  Exercises  of  endurance 
which  allow  of  the  elimination  of  the  whole  excess  of 
carbonic  acid  with  each  expiration,  lead  to  no  accumula- 
tion of  this  gas,  but  they  can  cause  an  accumulation  of 
the  nitrogenous  waste-products,  for  the  elimination  of 
these  does  not  begin,  as  we  have  shown,  for  three  or 
four  hours  after  the  muscular  work  which  has  caused 
their  formation.*  An  exercise  may  then  be  continued 
for  four  hours,  and  give  rise  throughout  this  time  to  the 
formation  of  nitrogenous  waste-products,  not  one  particle 
of  which  is  being  eliminated.  All  these  waste-products 
will  be  accumulated  in  the  blood  when  the  exercise  has 
come  to  an  end.  The  system  which  will  have  escaped 
the  effects  of  carbonic  acid,  a  gas  which  is  eliminated  as 
fast  as  it  is  formed,  will  not  escape  those  of  nitrogenous 
waste-products  which  will  have  accumulated  in  large 
quantities  in  the  blood.  There  will  be  after  the  exercise 
of  endurance  is  over,  a  true  uricaemia,  a  surcharge  of  the 
blood  with  uric  acid  compounds. 

This  result  explains  how  it  is  that  young  persons  who, 
thanks  to  the  adaptive  power  of  their  respiratory  organs, 
have  borne  with  impunity  an  exercise  of  speed,  and 
have  not  lost  breath,  can  easily  suffer  from  febrile  stiff- 
ness, and  even  from  febrile  overwork,  after  too  long  a 
walk. 

Gouty  persons  are,  like  children,  exposed  to  the  acci- 
dents of  consecutive  fatigue  after  exercises  of  endurance. 
They  have  already  a  constitutional  tendency  to  the 
accumulation  of  uric  acid  in  the  blood,  and  muscular 
exercise  causing  the  production   of  nitrogenous  waste- 

•  See  above  the  chapter  "Stiffness,"  p.  119. 


EXERCISES    OF    ENDURANCE.  269 

products  which  cannot  be  eHminated  as  fast  as  they  arc 
formed,  hence  there  is,  when  the  long-continued  work  is 
over,  an  abundance  of  uric  acid  compounds  in  the  blood. 
We  know  that  an  attack  of  gout  is  due  to  this  uric 
saturation  of  the  blood,  and  thus  are  explained  the 
attacks  of  gout  which,  in  gouty  subjects,  almost  inevitably 
follow  a  very  long  day's  shooting,  when  a  man  has  not 
been  prepared  by  gradual  training,  the  salutary  effects 
of  which  in  preventing  the  formation  of  deposits  of  urates 
we  have  already  studied. 

To  sum  up,  the  exercises  of  endurance  allow  of  the 
performance  of  such  work  with  great  economy  of  fatigue. 
They  give  the  system  the  benefit  of  a  supplementary 
acquisition  of  oxygen,  without  exposing  it  to  the  dangers 
of  forced  respiration.  They  quicken  the  circulation  of 
the  blood  without  fatiguing  the  heart  or  violently  dis- 
tending the  vessels.  In  a  word  they  spare  the  whole 
machine  during  work. 

But  if  they  preserve  the  system  from  the  accidents  of 
immediate  fatigue,  they  do  not  save  it  from  consecutive 
fatigue.  If  they  enable  it  to  escape  breathlessness,  this 
is  not  the  case  as  regards  stiffness. 

Moderate  and  prolonged  exercise,  that  in  which  the 
total  work  is  considerable,  but  well-divided,  is  suitable 
for  patients  whose  respiration  needs  management.  It 
cannot  be  prescribed  without  preliminary  training  for 
gouty  persons,  and   is  absolutely  unsuitable  for  children. 

Exercises  of  speed  are  well  suited  to  young  persons, 
who  easily  eliminate  carbonic  acid.  Exercises  of  en- 
durance are  better  suited  to  persons  of  ripe  age,  whose 
nitrogenous  tissues  resist  better  the  processes  of  dis- 
similation, and  form  less  the  nitrogenous  waste-products. 
Conscripts  are  excellent  for  manoeuvres  of  speed,  and 
veterans  for  manœuvres  of  endurance. 


19 


CHAPTER  Vî. 

MECHANISM   OF    DIFFERENT   EXERCISES. 

The  Principal  Action  and  the  Indirect  Actions  in  Exercise — Part 
Played  by  each  Part  of  the  Body  in  the  Chief  Exercises — Office 
of  the  Upper  Limbs — Gymnastic  Apparatus  :  especially  bring 
the  Arms  into  Action — Siispeiisio7i  and  Support  of  the  Body — 
Breastmor  2^xiàL.  Circling  in  the  Gymnasium — Rowing  ;  Fencing  ; 
Singlestick;  English  Boxing;  Dumb-bells  —  Office  of  the 
Lower  Limbs — Walking  and  Running  ;  French  Boxing  or 
Chausson — Usefulness  of  Exercises  of  the  Legs  in  developing 
the  Chest — Office  of  the  Pelvis — Flexion  of  Pelvis  on  Thorax 
in  Gymnastic  Exercises.  Development  thus  given  to  the 
Abdominal  Muscles  — The  best  "Girdle  agamst  Obesity" — • 
Office  of  the  Vertebral  Column  in  Exerc'se  —  Importance  of 
Position — The  Horseman  with  a  "Good  Seat" — Active  Share 
of  the  Vertebral  Column  in  Exercise.  Thrust  from  the  Loins 
— Leaping — Passive  Share  of  the  Vertebral  Column  in  Exercise 
— Orthopedic  Effects  of  Attitudes  of  "Suspension" — Swedish 
Gymnastics. 

I. 

To  understand  the  exact  mechanism  by  the  aid  of 
which  a  given  exercise  is  performed,  we  must  discover 
what  muscular  groups  are  brought  into  action,  and 
what  bony  levers  are  moved. 

This  analysis  is  not  always  easy,  for  besides  the 
principal  effort  and  most  apparent  movement,  every 
exercise  involves  secondary  efforts  which  associate  in 
the  work  parts  of  the  skeleton  or  regions  of  the  body 
which  we  should  not  have  expected  to  play  any  part. 
Different  regions  of  the  body  may  at  one  time  have 
the  chief,  and  at  another  only  an  indirect  share  in  an 
exercise  ;  and  we  see  the  arms,  the  legs,  the  head,  the 
neck  and  the  trunk,  become  in  turn  essential  agents  or 
accessory  factors  in  a  muscular  action.  But  in  general 
it  is  rare  for  an  isolated  region  of  the  body  to  be  ex- 
clusively  charged  with   the  work,  and    almost    always 


MECHANISM    OF    DIFFERENT    EXERCISES.         2/1 

several    separate    muscular    groups    are    in  association, 
and  contribute  with  greater  or  less  vigour. 

In  most  exercises  the    chief    part    is    played  by  the 
limbs;    the   vertebral  column,   the  pelvis,    the  ribs  and 
the  head    often    have    a    merely  secondary    action  :    if 
burthens  have  to  be  raised  or  weights  shifted,  it  is  by 
the    hands    they  are    seized  ;    if    the    body  has    to    be 
moved  it  is  the  legs  which  have  the  direct  part  through 
their  contact  with  the    ground,  or    the    arms    through 
being    the    means  of    suspension  in  various  gymnastic 
exercises.      But   wherever    a    very    energetic    effort    is 
needed  we  see  the  trunk  associated  with  the  movement 
of  the  limbs.     The  muscles  of  the  pelvis  come  to  the  aid 
of  the  lower  limbs.     Finally  the  muscles  of  the  vertebral 
column  and  the  ribs  are  associated  with  very  violent  move- 
ments of  the  limbs,  for  many  of  them  are  inserted  into  the 
scapula,  the  humerus,  the  pelvis,  and  the  femur. 

Often  all  the  muscles  of  the  body  seem  to  be  asso- 
ciated in  the  work  of  a  principal  muscular  group,  to 
work  with  it  for  a  definite  end.  This  association  is 
more  comolete  in  proportion  to  the  violence  of  the 
effort  ;  and  we  mav  see  the  work,  at  first  very  localised, 
when  'it  is  insignificant,  gradually  spread,  as  it  becomes 
more  considerable,  to  more  and  more  distant  parts,  and 
be  propagated  from  above,  downwards,  or  from  below, 
upwards,  according  to  the  nature  of  the  exercise,  from 
one  end  of  the  body  to  the  other. 

To  jump  with  the  feet  together  for  a  short  distance, 
only  the  lower  limbs  are  brought  into  play.  If  the 
distance  is  greater,  the  muscles  of  the  pelvis  and  the 
vertebral  column  are  associated  with  the  movement. 
If  the  man  wishes  to  jump  as  far  as  possible,  his  arms 
even  come  to  take  part  in  the  action,  and  they  are 
violently  swung  in  such  a  way  as  to  increase  the  mo- 
mentum of  the.  body.  .     . 

In  raising  a  very  light  dumb-bell  the  arm  alone  is  m 
action.  If  the  weight  is  heavier,  the  muscles  of  the  trunk 
are  associated  with  those  of  the  arm  and  shoulder.  If 
finally  the  weight  is  nearly  as  great  as  the  man  can  lift, 
we    see   the  extensor    muscles  of    the    legs   and   thighs 


2/2  PHYSIOLOGY    OF    BODILY    EXERCISE. 

contract  just  as  vigorously  as  the  others,  to  produce  a 
vigorous  upward  thrust.  Thus  a  muscular  action  which 
seems  at  first  to  be  a  simple  exercise  of  the  arms,  may 
render  necessary  a  very  energetic  action  of  the  legs. 

The  practical  consequence  to  be  deduced  from  these 
facts  is  of  some  importance.  Through  ignoring  the 
indirect  effects  of  muscular  movement,  we  might 
expose  a  patient  to  the  association  in  exercise  of  a 
damaged  region  which  it  would  be  important  to  spare. 

.  The  indirect  association  of  a  region  of  the  body  in 
work  has  sometimes  the  simple  object  of  furnishing  a 
fixed  point  of  application  to  the  limbs  in  action.  The 
indirect  muscular  action  is  in  this  case  a  necessity 
imposed  by  the  extreme  mobility  of  the  bony  pieces 
which  make  up  the  skeleton.  It  is  always  necessary 
that  one  extremity  of  a  muscle  should  have  a  fixed 
attachment,  in  order  that  the  other  extremity  may 
pull  efficiently  at  the  bone  into  which  it  is  inserted. 
The  greater  the  expenditure  of  force,  the  more  urgent 
becomes  the  necessity  of  providing  a  fixed  attachment 
to  the  muscles  in  action,  in  order  that  they  may  con- 
tract with  all  possible  energy.  When  the  movement 
represents  a  considerable  expenditure  of  force  it  is 
always  necessary  that  the  vertebral  column  and  trunk 
should  be  rigid,  they  representing  the  centre  to  which 
all  the  limbs  converge  ;  hence  arises  the  production  of 
effort  of  which  we  have  spoken  at  length  in  the 
chapter  on  Movements.  But  effort  itself  causes  a  mo- 
mentary stoppage  of  respiration,  and  a  compression  of 
the  great  veins  and  the  heart,  and  in  this  manner 
there  may  be  produced  a  profound  disturbance  in  the 
great  functions  of  the  economy  on  account  of  the  con- 
traction of  a  very  localised  muscular  group. 

The  examples  we  have  just  given  show  the  import- 
ance of  accessory  movements  and  of  indirect  muscular 
work  in  bodily  exercises.  The  more  we  analyse  these 
exercises,  the  more  we  are  impressed  by  the  intimate 
relation  between  all  the  muscular  groups,  and  between 
all  the  pieces  of    the    skeleton,  and    the  more  we  are 


MECHANISM    OF    DIFFERENT    EXERCISES.        2/3 

impressed  with  the  fact  that  the  local  effects  of  exer- 
cise often  influence  regions  which  are  at  a  considerable 
distance  from  that  which  seems  most  at  work. 

It  is  impossible  for  us  to  analyse  here  all  known 
exercises  and  to  show  the  part  in  their  performance 
which  devolves  on  this  or  that  region  of  the  body. 
Further,  it  is  not  our  object  to  make  a  complete  cata- 
logue of  all  the  exercises  which  it  has  pleased  the  fancy 
of  gymnasts  to  invent,  but  only  to  indicate  the  funda- 
mental notions  by  means  of  which  we  can  form  a 
judgment  of  the  hygienic  value  of  the  chief  exercises 
practised.  For  this  purpose  it  will  be  most  easy  to 
glance  at  the  various  regions  of  the  body,  and  to  point 
out  broadly  what  direct  or  indirect  part  each  of  them 
usually  plays  in  the  different  exercises  practised. 

II. 

In  most  exercises  the  principal  and  direct  share 
devolves  on  the  limbs,  and  the  indirect  on  the  trunk 
which  associates  in  the  work  of  the  arms  and  legs,  either 
by  a  muscular  effort  in  the  same  direction,  or  by  an  atti- 
tude favourable  to  the  performance  of  the  movement. 

The  a,rm  appears  to  be  the  object  of  all  the  exercises 
of  modern  gymnastics.  Most  of  the  exercises  per- 
formed in  a  gymnasium  need  as  a  preliminary  that  a 
rope  or  bar  should  be  seized.  The  upper  limbs  must 
then  "  suspend  "  the  body  to  the  apparatus  held  in  the 
hands,  or  "  support  "  it  when  raised  above  the  hands. 
The  suspension  and  support  of  the  body  are  the  funda- 
mental positions  of  gymnastics  with  apparatus. 

In  these  exercises  the  arms  have  to  move  the  weight 
of  the  body  in  different  directions.  They  usurp  in  a 
manner  the  office  of  the  legs.  But  what  the  legs  ac- 
complish with  ease  by  means  of  their  powerful  muscular 
masse?,  the  arms  perform  with  difficulty,  and  must  use 
all  their  energy  to  raise  the  body,  as  when  it  is  necessary 
to  pass  from  the  attitude  of  suspension  to  that  of  sup- 
port in  the  movement  known  as  breasting.  A  man  who 
performs  a  breast  does  work  represented  by  the  weight 


2/4  PHYSIOLOGY    OF    BODILY    EXERCISE. 

of  his  body  multiplied  by  twice  the  length  of  his  arms. 
Most  gymnastic  exercises  thus  throw  a  considerable 
work  on  the  upper  limbs  ;  hence  the  arms  become 
quickly  and  greatly  developed  in  those  who  practise 
gymnastics  with  apparatus. 

Work  of  the  arms  is  necessary  in  exercises  Avhich 
bring  about  the  displacement  of  more  or  less  heavy 
weights,  the  body  remaining  on  the  ground.  Thus, 
dumb-bell  exercise  needs  an  expenditure  of  the  muscular 
force  of  the  arms  in  proportion  to  the  weight  of  the 
masses  raised.  But  never,  at  least  in  gymnastic  exer- 
cises, are  the  weights  as  heavy  as  the  human  body. 
Hence  the  muscles  and  bones  of  the  shoulder  do  not 
perform  as  much  work  in  most  of  the  exercises  in  which 
the  feet  do  not  move,  as  in  those  needing  the  support  or 
suspension  of  the  body  by  the  arms. 

When  a  gymnast  balances  on  his  hands,  with  his  feet 
in  the  air,  he  makes  his  shoulders  support  the  whole 
weight  of  his  body,  just  as  his  hips  do  in  the  ordinary 
upright  posture  ;  but  the  pelvis  with  its  solid  bony  girdle 
made  of  thick  bones,  strongly  connected,  is  very  fitted 
for  support,  and  easily  transmits  the  weight  of  the  body 
to  the  two  femurs  firmly  articulated  in  deep  cavities 
hollowed  in  solid  bones  ;  whereas  the  shoulder  joint  is 
in  no  way  fitted  for  such  work.  While  the  body  is  sup- 
ported by  the  arms,  the  muscles  surrounding  the  hu- 
merus, the  scapula,  and  the  clavicle  must  contract  very 
energetically  to  fix  these  very  movable  bones,  and  thus 
create  an  artificial  attitude  at  the  expense  of  a  consider- 
able work  of  the  muscles  of  the  neck,  chest  and  back. 

We  shall  see,  in  speaking  of  exercises  which  produce 
deformity,  the  consequences  of  this  exaggerated  action 
of  the  m.uscles  about  the  shoulder. 

Most  of  the  exercises  of  gymnastics  with  apparatus 
need  constantly  the  support  of  the  body  on  the  arms, 
or  the  passage  from  suspension  to  support,  as  in  the 
various  breasting  movements.  Plence  it  is  especially  in 
men  devoted  to  the  trapeze,  the  horizontal  bar,  the 
rings,  the  parallel  bars,  that  we  observe  this  excessive 
development  of  the  muscles  about  the  shoulder,  and  this 


MECIIANISxM    OF    DIFFERENT    EXERCISES.        2/5 

projection  of  the  fleshy  masses  of  the  neck,  which  often 
becomes  ungraceful  from  its  exaggeration. 

Many  other  exercises  may  demand  great  expenditure 
of  force  from  the  muscles  of  the  arm  without  associatiner 
in  their  work  so  disproportionate  an  effort  of  the  shoul- 
der. Rowing  for  instance  needs  vigorous  pulling  of  the 
oar,  but  this  does  not  submit  the  shoulder  joint  to  the 
violent  pressure  which  occurs  in  the  gymnastic  exercises 
above  described.  In  rowing  the  arms  perform  alternate 
movements  of  flexion  and  extension  combined  with 
movements  of  abduction  and  adduction.  If  the  exercise 
is  vigorous,  the  trunk  associates  in  the  work  by  bending 
forwards  in  a  manner  to  favour  the  extension  of  the 
arms,  then  the  whole  body  undergoes  the  movement  of 
extension,  with  which  is  associated  a  thrust  of  the  legs 
and  thighs  to  continue  the  backward  movement  begun 
by  the  flexion  of  the  arms.  Thus,  in  handling  an  oar, 
the  movements  accord  with  the  function  of  each  muscle 
and  each  lever  employed. 

We  shall  see  the  importance  of  this  fact  in  studying 
exercises  which  produce  deformity. 

In  boxing,  quarter-staff,  single-stick,  and  fencing,  the 
muscles  also  act  whether  simultaneously  or  singly,  with 
only  an  insignificant  load,  or  even  with  none  at  all. 
Hence  the  upper  limbs  do  not  present,  in  persons 
devoted  to  these  exercises,  the  conformation  noticeable 
in  gymnasts,  oarsmen,  and  occupations  needing  the 
movement  of  heavy  masses.  In  prize-fighters  the  arms 
are  very  muscular,  but  this  development,  which  adds  to 
the  force  of  the  blow,  is  obtained  by  accessory  exer- 
cises, such  as  dumb-bells. 

The  legs  are  the  limbs  most  naturally  exercised  in  the 
ordinary  circumstances  of  life.  It  is  on  them  that  in 
man  devolves  the  function  of  locomotion.  They  can  per- 
form, besides  walking  and  running,  the  natural  paces,  a 
number  of  complicated  movements,  such  as  those  per- 
formed in  dancing. 

French  boxing  needs  on  the  part  of  the  legs  work 
which  is  quite  different  from  walking,  and  one  which 
rather  resembles  dancing.     The  peculiarity  of  the  move- 


276  PHYSIOLOGY    OF    BODILY    EXERCISE 

ment  of  this  exercise  is  to  force  the  body  to  support 
itself  on  one  leg  whilst  the  other  gives  a  kick  ;  it  is 
difficult  to  keep  balance  in  these  attitudes  in  which  the 
trunk  associates  in  every  movement  of  the  limbs.  To 
counterpoise  the  leg  which  carries  the  foot  towards  the 
opponent's  figure,  the  body  swings  on  to  the  other  limb 
by  a  lateral  flexion  of  the  lumbar  spine,  then  the  great 
muscles  of  the  pelvis  strongly  extend  the  thigh,  on 
which  the  leg  is  itself  also  strongly  extended.  But  the 
extension  of  the  thigh  presupposes  the  fixation  of  the 
pelvis,  which  itself  cannot  be  fixed  unless  the  ribs  are 
rendered  motionless  by  a  deep  inspiration  with  breath 
held  at  the  end  of  it.  Hence  an  "  effort  "  must  be  made, 
and  for  this  reason  a  well-applied  kick  is  almost  always  ac- 
companied by  a  kindof  groaningvvhich  indicates  the  brisk 
expulsion  of  the  air  which  had  been  retained  in  the  lungs. 

The  legs  can  perform  much  work  without  fatigue 
because  they  possess  powerful  muscular  masses.  No 
exercise  can  produce  for  a  very  short  time  a  sum  of 
work  comparable  to  that  performed  by  a  man  who  goes 
quickly  up  a  staircase,  or  runs  up  a  steep  slope.  If  we 
try  to  perform  an  equivalent  work  by  means  of  the 
arms  in  climbing  up  a  ladder,  fatigue  very  promptly 
stops  the  exercise,  because  the  work  required  from  the 
muscles  in  action  is  too  considerable  for  their  size.  But 
breathlessness  is  proportional  to  the  total  quantity  of 
work  done  in  a  given  time  ;  hence  the  exercises  of  the 
legs,  if  they  do  not  induce  prompt  muscular  fatigue,  very 
quickly  lead  to  breathlessness. 

Here  is  a  peculiarity  worthy  of  note,  and  of  great  prac- 
tical importance.  The  exercises  which  make  the  legs  work 
actively  almost  all  need  the  co-operation  of  the  thorax. 
Running,  walking  up  hill,  leaping,  exaggerate  the  move- 
ments of  the  ribs  by  the  greater  activity  they  give  to  the 
respiration.  Hence  we  draw  a  practical  conclusion  which 
we  shall  develop  further  on  :  the  exercises  of  the  legs  are 
generally  to  be  preferred  to  those  of  the  arms  when  we 
wish  to  develop  the  chest  and  raise  the  ribs. 

i'lc  pelvis  associates  actively  in  all  the  exercises  in 


MFXHANISM    OF    DIFFERENT    EXERCISES.         277 

which  the  body  keeps  the  erect  posture.  Its  position  as 
intermediary  between  the  vertebral  cohimn  which  it  sup- 
ports and  the  legs  by  which  it  is  supported,  obliges  it  to 
take  part  in  all  the  energetic  movements  of  the  trunk,  as 
well  as  in  those  of  the  vertebral  column  and  the  thorax. 

In  bodily  exercises,  the  movements  of  the  pelvis  are 
almost  always  indirect  and  accessory.  It  is  displaced  in 
walking,  in  running,  in  leaping,  always  supporting  the 
weight  of  the  body,  and  is  thus  subject  to  shocks  which 
its  massive  structure  enables  it  to  endure  without  injury. 

In  gymnastic  exercises  which  need  the  suspension  of 
the  body  by,  or  its  support  on,  the  hands,  the  pelvis  is 
often  displaced,  but  then  it  has  not  to  support  the  weight 
of  the  trunk,  and  bears  only  that  of  the  lower  limbs. 
These  exercises  demand  every  moment  a  movement 
which  hardly  ever  occurs  in  the  ordinary  actions  of  life, 
the  flexion  of  the  pelvis  on  the  trunk.  The  result  of  this 
movement  is  to  double  up  the  body,  and  draw  the  limbs 
towards  the  chest.  To  circle  the  trapeze  and  to  perform 
a  like  movement  on  the  rings  and  on  the  parallel  bars, 
flexion  of  the  pelvis  on  the  trunk  is  necessary.  It  is  to 
the  abdominal  muscles  that  is  assigned  the  office  of 
flexing  the  pelvis  on  the  trunk,  or  conversely  of  the  trunk 
on  the  pelvis.  Hence  these  muscles  become  very  firm  and 
very  thick  in  professional  gymnasts.  Hence  the  rarity  of 
big  bellies  in  persons  who  do  much  work  on  the  trapeze  : 
the  firmness  of  the  muscular  walls  of  the  abdomen  being 
an  excellent  preservation  against  fatty  deposits.  Firm 
and  vigorous  abdominal  muscles  form  the  best  "  girdle 
against  obesity." 

III. 

The  vertebral  column  represents  the  axis  of  the  body  ; 
it  is  made  up  of  a  great  number  of  movable  pieces  which 
can  undergo  displacements  together  or  separately.  There 
is  no  part  of  the  body  which  more  often  associates  in 
work,  either  as  a  whole,  or  one  of  its  sections  alone. 

Different  bodily  exercises  and  different  kinds  of 
labour  make  very  different  uses  of  the  vertebral  column. 
It  is  sometimes  associated  in  movement  as  a  counter- 


2/8  PHYSIOLOGY    OF    BODILY    EXERCISE. 

poise  to  maintain  equilibrium  endangered  by  a  dis- 
placement of  the  centre  of  gravity.  It  is  a  kind  of 
balance,  the  changes  of  position  of  which  are  simply 
compensatory.  Thus  we  stoop  forwards  or  backwards, 
according  as  we  are  carrying  a  load  behind  or  in  front. 

Many  movements  of  the  limbs  need  a  co-operation  of 
the  vertebral  column,  not  for  any  reason  of  balance,  but 
owing  to  the  necessity  of  a  particular  attitude  favourable 
to  the  performance  of  the  work.  Certain  professional 
labours  need  a  stooping  position,  and  the  vertebral 
column  associates  in  the  work  of  the  arms  by  bending 
forwards  or  to  the  side.  In  a  man  using  a  pickaxe,  the 
work  of  the  arms  must  be  accompanied  by  a  certain 
bending  of  the  trunk  to  allow  the  hands  which  hold  the 
tool  to  approach  the  ground. 

In  bodily  exercises  the  part  played  by  attitude  is  very 
important.  The  success  of  a  gymnastic  movement 
depends  almost  always  upon  good  position  of  the  body. 
Generally  the  arms  begin  a  movement,  but  the  muscles 
of  the  body  finish  it.  On  the  rings,  the  trapeze,  the 
parallel  bars,  no  movement  can  be  performed  unless  the 
vertebral  column  associates  in  the  movement  of  the  arms, 
whether  by  flexion  or  by  extension. 

In  riding,  the  active  work  is  apparently  done  by  the 
thighs,  which  by  their  energetic  pressure  must  make  the 
horseman,  so  to  speak,  stick  to  his  saddle.  But  firmness 
of  seat  comes  rather  from  the  perfectly  balanced  attitude 
of  the  trunk.  All  horsemen  know  that  a  man  with  a 
"  good  seat,"  that  is  to  say,  having  an  attitude  favourable 
to  equilibrium,  needs  very  little  force  to  keep  him  in  the 
saddle.  Further,  in  the  shocks  of  rapid  riding,  the  verte- 
bral column,  thanks  to  the  extreme  mobility  of  the  pieces 
of  which  it  is  made  up,  undergoes  a  series  of  local  move- 
ments in  the  lumbar  and  dorsal  regions,  which  cause  the 
movements  of  the  horse  to  be  deadened  and  lost  without 
displacement  of  the  trunk. 

The  vertebral  column  sometimes  associates  very  in- 
timately with  the  miOvements  of  the  limbs,  and  accom- 
panies them  in  their  changes  of  direction.  In  fencing, 
for  instance,  in  the  movem.ents  of  attack,  in  proportion  as 


MECHANISM    OF    DIFFERENT    EXF.KCISES.        279 

the  arm  is  stretched,  the  vertebral  column  is  lengthened 
by  a  movement  of  forced  extension,  and  when  the  fencer 
lunges,  stretching  -his  arm  towards  his  adversary,  the 
dorsal  spine  is  strongly  projected  in  the  same  direction, 
and  for  this  it  is  necessary  to  lean  towards  the  side  of  the 
threatening  arm,  in  such  a  manner  that  the  foil,  the  right 
arm,  and  the  vertebral  column,  tend  to  place  themselves 
in  the  same  axis  and  form  a  simple  straight  line. 

This  association  of  the  vertebral  column  with  the 
movements  of  the  arm  is  also  observed  in  the  exercises  in 
which  the  muscles  of  the  trunk  must  help  and  reinforce  the 
action  of  the  upper  limbs.  If  we  endeavour  to  give  a 
violent  thrust  with  the  hand,  the  spine,  in  order  to  asso- 
ciate in  this  movement  as  efficiently  as  possible,  must 
bend  to  one  side,  to  place  itself  in  the  axis  of  the  arm, 
for  this  direction  will  be  the  most  favourable  for  the 
assistance  by  all  the  pressure  of  the  trunk  of  the  move- 
ment performed  by  the  extensors  of  the  arms.  A  blow 
with  the  fist,  say  boxers,  must  be  given  with  the  loins 
and  backed  up  by  the  whole  body. 

When  the  vertebral  column  thus  comes  to  the  assist- 
ance of  the  arms,  whether  actively  or  passively,  one  of 
two  things  may  happen,  either  the  direction  of  the 
vertebral  column  is  associated  w^ith  that  of  one  arm  only, 
as  occurs  in  fencing,  and  then  the  bony  column  is  in- 
clined towards  the  arm  in  action,  and  bends  to  the  right 
or  left,  as  the  case  may  be;  or  the  vertebral  column 
associates  with  both  arms  at  once,  and  then  the  direction 
of  displacement  is  not  a  lateral  one,  but  an  exaggeration 
of  its  natural  curves. 

In  fact  the  shoulders  are  on  a  level  with  the  upper  end 
of  the  dorsal  curve  of  the  spine.  If  both  arm.s  are 
stretched  out  above  the  head,  holding  a  heavy  dumb-bell, 
the  direction  of  the  arms  is  parallel  to  the  general 
direction  of  the  vertebral  columm.  But  this  column  is 
not  straight  ;  it  has  several  curves,  of  which  one  begins 
at  the  seventh  cervical  vertebra,  that  is  at  the  level  of  the 
shoulders,  and  ends  at  the  twelfth  dorsal  vertebra.  The 
twelve  dorsal  vertebrae  thus  form  an  arc,  of  v/hich  the 
chord  would  be  represented  by  a  line  having  exactly  the 


28o  PHYSIOLOGY    OF    BODILY    EXERCISE. 

direction  of  the  force  which  is  being  resisted  by  the  arms. 
The  vertebral  column,  in  association  with  the  verticalresist- 
ance  of  the  upper  limbs,  undergoes  a  pressure  which  has 
the  same  effect  on  its  dorsal  curvature  as  is  exercised  on  a 
bow  by  tension  of  its  string;  viz.,  its  convexity  is  increased. 

Finally,  the  vertebral  column  may  play  the  principal 
part  in  a  muscular  effort.  Many  movements  are  per- 
formed by  a  thrust  from  the  loins  which  sometimes  flexes 
the  trunk,  as  in  ringing  a  heavy  bell,  and  sometimes 
extends  it,  as  in  raising  a  heavy  load  from  the  ground. 
Many  exercises  necessitate  alternate  movements  of 
flexion  and  extension  of  the  vertebral  column.  Rowing, 
for  instance,  brings  the  vertebral  column  into  play  with 
each  stroke,  for  it  is  flexed  in  carrying  the  oar  back,  and 
vigorously  extended  in  pulling  the  stroke. 

In  a  standing  jump,  the  vertebral  column  is  brought 
actively  into  play.  The  jumper,  to  gain  impetus,  stoops, 
and  then  vigorously  straightens  himself  like  a  relaxed 
spring.  In  jumping  with  a  run,  the  impetus  thus  gained 
is  used  to  launch  the  body,  but  once  in  the  air  the 
jumper  has  to  bring  into  play  the  muscular  power  of 
the  dorsal  region.  In  a  very  curious  instantaneous 
photograph  given  by  Marey  *  we  see  ten  successive 
attitudes  of  a  man  doing  a  high  jump,  and  amongst 
these  attitudes  corresponding  to  different  moments  of 
the  leap,  there  are  four  or  five  in  which  we  see  that  the 
vertebral  column,  at  first  strongly  flexed  by  a  movement 
which  raises  the  knees  and  draws  them  towards  the 
trunk,  is  two  tenths  of  a  second  later  in  a  position  of 
forced  extension  owing  to  a  swinging  movement  of  the 
trunk  which  carries  the  lower  limbs  as  far  forwards  as 
possible.  The  body  of  the  jumper  is  then  in  a  very 
oblique  position  to  the  surface  of  the  ground.  The  axis 
of  the  trunk  makes  an  angle  of  45°  with  the  horizontal, 
which  is  evidently  incompatible  with  standing  on  the 
feet.  A  vigorous  exertion  of  the  loins  is  necessary  to 
replace  the  vertebral  column  in  the  vertical  position, 
under  pain  of  falling  backwards. 

•  Marey.     La  Machine  Animale. 


MECHANISM    OF    DIFFERENT    EXERCISES.        28 1 

Thus  every  moment,  in  gymnastic  exercises,  the 
vertebral  column  actively  associates  with  the  action  of 
the  limbs  to  finish  a  movement  which  they  have  begun. 

Most  exercises  performed  with  the  aid  of  apparatus 
seem  to  make  only  the  arms  work,  but  they  really  need 
the  very  active  concourse  of  the  muscles  which  move 
the  spine.  Often  in  breastmg  movements  the  muscular 
action  is  facilitated  by  an  imperceptible  movement  of 
flexion  of  the  vertebral  column  which  curves  the  back, 
or  by  an  effort  of  extension  which  hollows  it. 

In  the  cases  we  have  quoted,  the  vertebral  column  has 
an  active  part,  through  the  muscles  attached  to  it,  which 
energetically  participate  in  the  work.  There  are  other 
circumstances  in  which  the  bony  column  has  a  passive 
share,  and  simply  is  influenced  by  the  weight.  In  a  man 
hanging  by  the  arms  from  a  trapeze,  whose  body  is 
vertical  from  its  own  weight,  all  the  muscles  of  the  back 
are  completely  relaxed,  but  the  vertebrse  to  which  they 
are  attached  undergo  the  traction  of  the  weight  of  the 
body,  suspended  in  space.  The  point  of  suspension, 
which  is  at  the  level  of  the  shoulders,  corresponds  to  the 
first  dorsal  or  last  cervical  vertebra.  From  this  point  of 
attachment  the  whole  body  is  subject  to  the  weight 
which  draws  it  down,  and  it  is  easy  to  understand  how 
the  dorsal  curvature  of  the  spine  becomes  diminished, 
for  all  the  movable  pieces  of  which  it  is  made  up  tend 
to  take  the  direction  of  a  plumb-line. 

The  same  result  is  brought  about  if  the  body,  instead 
of  being  suspended  by  the  arms,  is  supported  by  them. 
Instead  of  holding  his  arms  above  his  head  and  seizing 
a  bar,  the  gymnast  can,  with  his  legs  downward,  rest  on 
the  parallel  bars  supported  by  his  arms.  In  this  case 
the  point  of  support  will  be  at  the  same  level  as  was  just 
before  the  point  of  suspension,  and  the  body  will  be  just 
as  passively  abandoned  to  the  weight  which  tends  to 
efface  the  curves  of  the  spine. 

Numerous  gymnastic  movements  need  that  the  body 
should  remain  for  a  moment  in  this  inert  condition, 
supported,  or  suspended  by  the  arms.  But  these  are 
usually   merely   preliminary   positions,   and  the    spinal 


282  PHYSIOLOGY    OF    BODILY    EXERCISE. 

column  is  soon  associated  in  various  evolutions  which  no 
longer  allow  it  to  play  a  merely  passive  part. 

On  the  trapeze,  the  rings,  the  horizontal  bar,  the  period 
of  suspension  of*  the  body  by  the  arms  is  merely  a  sort 
of  short  preface  to  the  exercise.  Climbing  a  ladder  or  a 
rope  by  the  hands  alone,  allow,  on  the  contrary,  a  man 
to  leave  throughout  the  whole  exercise  his  trunk  inert 
and  supple,  while  the  arms  alone  are  at  work. 

On  the  parallel  bars  the  body  is  supported  by  the 
arms,  and  remains  inert  during  the  movements  of 
horizontal  progression  brought  about  by  the  regular 
movements  of  the  hands.  A  great  number  of  the 
movements  performed  on  the  parallel  bars  allow  the 
spinal  column  to  benefit  by  the  action  of  the  weight 
which  tends  to  lessen  its  curves. 

From  an  orthopaedic  standpoint,  the  mechanism  of  the 
exercises  of  which  we  have  just  been  speaking,  has  been 
made  use  of  in  the  correction  of  deviations  of  figure. 
Most  of  the  cures  of  the  "  Swedish  "  gymnastics  are 
based  upon  the  method  of  suspending  the  patient  by 
the  hands  or  supporting  him  by  the  arms,  the  body 
being  abandoned  to  the  weight  which  tends  to  straighten 
the  crooked  spine. 

The  compass  of  this  volume  will  not  allow  us  to  study 
in  detail  the  different  exercises,  and  to  analyse  and 
explain  their  mechanism,  that  is  the  manner  in  which 
they  bring  into  play  the  different  bony  levers  of  which 
the  animal  machine  is  made  up.  We  have  merely  been 
able  broadly  to  delineate  the  mode  of  action  of  each 
part  of  the  body  in  muscular  work,  and  to  indicate  the 
part  played  by  the  limbs,  the  pelvis,  the  vertebral 
column,  and  the  ribs  in  the  more  common  movements. 

This  rapid  sketch  has  for  its  special  object  to  make  the 
changes  comprehensible  which  each  exercise  can  produce 
in  the  different  regions  of  the  body,  whether  by  chiefly  de- 
veloping certain  muscular  groups  which  act  more  than  the 
others,  or  by  modifying  the  direction  of  certain  bones  or 
bony  systems,  which  support  directly  or  indirectly 
pressures  and  shocks,  or  are  placed  .in  vicious  attitudes. 


PART    V. 
THE    RESULTS   OF   EXERCISE. 

GENERAL  EFFECTS    OF  EXERCISE — EXERCISES    WHICH 
DEVELOP  THE        CHEST — LOCAL        EFFECTS      OF 

EXERCISE—  EXERCISES  WHICH  PRODUCE  DE- 
FORMITY— EXERCISES  WHICH  DO  NOT  PRODUCE 
DEFORMITY. 


CHAPTER    I. 

GENERAL   EFFECTS   OF   EXERCISE. 

V^arying  Nature  of  the  Effects  of  Exercise — Its  two  Chief  Resnirs, 
the  Losses  and  the  Gains — Increased  Activity  of  Combustions, 
Resulting  in  the  Using-up  of  the  Reserve  Materials —Why  is 
Nutrition  more  Active  ?—  Part  Played  by  Oxygen — The  "  Need 
for  Exercise";  to  What  it  is  Due —Accumulation  of  Reserve 
Materials— Sluggish  Nutrition— Why  an  Inactive  iVIan  "  Feirs 
Fatigue" — Itibuthcient  Exercise  —  Unwholesome  Effects  on 
Nutrition — Slackening  of  the  Process  of  Dissimilation — Obesity 
— Deficient  Oxygea  and  Excess  of  Reserve  Materials — In- 
complete Oxidations  —  Gout — Necessity  for  Exercise— Effects 
Common  to  all  Forms  of  Muscular  Work — Special  Effects 
according  to  the  Quality  of  the  Work — Observation  on  Horses 
— Trotting  and  Walking. 

I. 

If  we  go  into  a  gymnasium  and  examine  a  group  of 
men  who  are  doing  t-'xercise  by  Mie  doctor's  orders,  we 
can  hardly  believe  that  the  same  medicament  can  be 
suitable  for  such  different  temperaments,  for  such  widely 
opposed  disturbances  of  health.  We  ask  how  the  same 
method  of  treatment  can  be  advantageously  applied  to 
men  of  a  stout  build,  with  red  faces  and  exuberant  flesh, 
and  to  men  who  are  thin,  pale,  and  emaciated. 

It  will  surprise  us,  however,  after  a  few  Vv^eeks,  when 
we  come  to  study  afresh  these  different  types,  to  find 
how  much  less  contrast  they  now  exhibit  in  structure 
and  physiognomy.  The  heavy  man  has  lost  weight, 
while  the  man  who  was  too  light  has  gained  it  ;  the 
former  has  no  longer  the  violet  tint  which  announced 
vascular  plethora  ;  the  latter,  on  the  contrary,  has  a 
brighter  colouring  :  the  blood  flows  to  his  formerly  dis- 
coloured cheeks,  and  his  whole  appearance  announces  a 
more  intense  life. 
20 


2S6  PHYSIOLOGY    OF    BODILY    EXERCISE. 

The  practice  of  exercise  tends  to  impress  an  identical 
seal  on  the  most  various  temperaments,  and  to  reduce  to 
the  same  type  the  most  opposite  constitutions. 

This  is  because  exercise  produces  in  the  system  two 
absolutely  different  effects  ;  it  increases  the  process  of 
assimilation,  thanks  to  which  the  body  gains  new  tissues, 
and  it  accelerates  the  process  of  dissimilation,  which 
leads  to  the  destruction  of  certain  materials. 

The  process  of  dissimilation  is  more  active,  owing  to 
the  greater  intensity  of  the  vital  combustions.  A  muscle 
which  works  is  a  muscle  which  becomes  heated,  and  this 
cannot  occur  without  the  burning  of  a  certain  quantity 
of  tissue.  The  excessive  production  of  heat  which 
accompanies  work,  the  rapid  combustion  of  certain 
materials  of  the  body,  and  their  elimination  from  the 
system  as  waste-products  of  combustion,  these  are  the 
causes  of  loss  of  weight  in  exercise. 

It  is  not  so  easy  to  explain  increase  in  body-weight, 
under  the  influence  of  methodical  work. 

''  Under  the  influence  of  gymnastic  exercise,"  says 
Dujardin-Baumetz,  "the  activity  of  the  cellular  func- 
tions increases  and  becomes  more  regular,  the  intra- 
cellular combustions  become  more  active  ;  the  leuco- 
maïnes,  these  toxic  materials  which  the  organic  cell  is 
constantly  manufacturing,  are  more  actively  elimiinated, 
and  the  general  effect  is  that  the  fats  are  burned  up, 
the  cellular  functions  regulated,  there  is  established  an 
equilibrium  between  the  cells  of  the  spinal  cord  and 
those  of  the  brain,  in  a  word,  general  nutrition  becomes 
more  active."  * 

With  due  deference  to  the  eminent  professor,  we 
cannot  help  thinking  that  the  explanation  he  gives  of  the 
effects  of  exercise  is  insufficient.  It  simply  states  a  fact  : 
nutrition  becomes  more  active.  We  can  well  understand 
how  increased  activity  of  nutrition  implies  the  idea  of 
more  active  absorption  of  materials  derived  from  the 
food,  and  the  more  regular  deposit  of  these  materials  in 
the  living  organs  and  tissues.     But  why  does  nutrition 

®  BuUolin  de  thérapeutique,  May  15,  1887. 


GENERAL    EFFECTS    OF    EXERCISE.  28/ 

become  more  active  under  the  influence  of  exercise  ? 
Because,  says  Dujardin-Baumetz,  the  activity  of  the 
cellular  functions  increases  and  becomes  more  regular. 
It  remains  to  determine  how  muscular  movement 
increases  and  regulates  the  activity  of  the  cells. 

It  seems  to  us  impossible  to  explain  the  greater 
activity  of  the  cells,  as  a  result  of  exercise,  other  than 
by  an  increase  of  the  stimulus  which  they  receive  from 
the  nerves  and  the  blood.  We  know,  in  fact,  that  the 
properties  of  the  cells  are  dependent  on  these  two 
agents.  If  we  cut  the  nerve-fibres  going  to  glands,  their 
secretions  are  .profoundly  altered  or  completely 
suspended.  But,  on  the  other  hand,  the  nerves  them- 
selves are  dependent  on  the  blood,  for  ligature  or 
obstruction  of  the  nutrient  vessels  of  the  brain  or 
spinal  cord  instantly  abolish  the  functions  of  these 
organs. 

It  is  then  in  the  blood,  the  "  regulator  of  the  nervous 
system,"  that  we  must  ultimately  seek  the  causes  capable 
of  modifying  "  the  cellular  functions  "  which  preside 
over  nutrition.  Now  exercise  profoundly  modifies  the 
composition  of  the  blood. 

At  first  sight  the  changes  undergone  by  the  blood 
seem  to  be  of  a  nature  to  hinder  the  working  of  the 
nerve-cells.  In  fact  Claude  Bernard  has  shown,  by 
analysing  the  blood  returned  from  a  muscle  at  work, 
that  it  is  black,  and  contains  no  oxygen,  while  the 
venous  blood  from  the  same  muscle  at  rest  contains 
nearly  as  much  oxygen  as  is  present  in  arterial  blood. 
Now  ^ve  know  that  venous  blood  charged  with  carbonic 
acid  and  deprived  of  oxygen,  exercises  on  nerve-cells 
and  on  all  the  organic  elements  a  stupefying  action 
which  tends  to  render  their  functions  less  active. 

But  the  consecutive  effects  of  exercise  differ  greatly 
from  the  immediate  effects,  and,  if  the  blood  is  deficient 
in  oxygen  during  the  work,  it  contains,  on  the  contrary, 
much  more  than  usual  soon  after  the  work  is  over.  For 
during  exercise,  if  the  combustions  are  increased, 
respiration  is  greatly  quickened.  The  oxygen  which 
enters  by  the  lungs   talies  the  place  of   that   which  is 


288  PHYSIOLOGY    OF    BODILY    EXERCISE. 

used  in  the  combustions,  and  the  final  result  of  exercise 
is  not  a  loss,  but  a  gain  of  this  gas. 

Exercise  introduces  more  oxygen  into  the  system  than 
is  actually  needed  for  the  combustions,  at  least,  direct 
observation  seems  to  show  that,  in  the  period  which 
follows  violent  exercise,  the  blood,  after  being  for  a  short 
time  surcharged  with  carbonic  acid,  becomes  on  the 
other  hand  surcharged  with  oxygen.  In  fact,  if  we 
observe  a  man  who  has  just  been  performing  muscular 
work  sufficiently  intense  to  influence  respiration,  we  find 
that  after  having  exhibited  the  phenomena  of  breath- 
lessness  due  to  excess  of  carbonic  acid,  he  shows  in  the 
end  a  remarkable  diminution  of  the  respiratory  need 
and  a  notable  slackening  of  the  respiratory  movements. 

When  we  observe  a  man  resting  after  intense  and 
sustained  muscular  work,  we  see  that  his  respiration,  at 
first  markedly  accelerated,  gradually  returns  to  its 
ordinary  rhythm,  and  if  we  continue  the  observation  we 
see  that  the  respiratory  movements  become  still  slower, 
and  fall  below  the  normal  rate. 

During  an  ascent  in  the  Eastern  Pyrenees,  we  made 
the  following  observation  on  ourselves  and  on  a  guide. 
At  the  foot  of  a  hill  when  our  breathing  was  uninfluenced 
by  exercise,  it  was  14  per  minute  in  our  guide,  and  16  in 
ourselves.  After  going  up  a  very  steep  incline  for 
twenty  minutes  the  guide's  breathing  was  28,  and  our 
own  30.  But  after  resting  for  six  minutes  the  rate  had 
fallen  in  the  one  to  10,  and  in  the  other  to  9.  The  final 
result  of  the  exercise  had  been  a  diminution  of  the 
respiratory  need,  a  temporary  apnœa.  Now  we  know 
that  an  increase  in  the  oxygen  contained  in  the  blood 
causes  a  diminution  of  the  respiratory  need.* 

'  Thus  a  man  taking  exercise  lays  up  a  provision  of 
oxygen.  This  gas  becomes  as  it  were  stored  amongst 
the  anatomical  elements  of  which  he  organism  is  built 
up  ;  it  is  especially  bound  to  the  red  blood-discs,  which 
become  redder,  and  their  vivifying  power  is  increased. 
This  more  living  blood,  if  we  may  use  the  expression, 

•  RicheU     Revue  Scientifique,  May  4,  1887,  p.  725. 


GENERAL    EFFECTS    OF    EXERCISE.  289 

carries  to  the  orc^ans  a  salutary  stimulus  which  increases 
the  activity  of  their  functions. 

It  has  been  experimentally  proved  that  all  the  elements 
of  the  system  undergo  a  kind  of  awakening  of  their 
energies  under  the  influence  of  strongly  oxygenated 
blood.  If  such  blood  be  injected  we  see  glands  secrete 
more  actively,  the  contractility  of  fatigued  muscles  re- 
appear, and  even  signs  of  life  in  the  cerebral  cells  of  a 
decapitated  animal.  * 

We  understand  how,  under  the  influence  of  powerfully 
oxygenated  blood,  the  glands  of  the  alimentary  canal 
can  more  actively  secrete  the  fluids  necessary  for  the 
elaboration  of  the  food  ;  how  the  contractile  fibres  of  the 
intestine  perform  their  peristaltic  movements  which  are 
as  necessary  for  digestion,  with,  more  energy  ;  how  the 
absorbent  vessels  draw  to  themselves  by  a  more  power- 
ful endosmotic  process,  the  nutritive  molecules  elaborated 
in  the  digestive  tract.  Thus  the  acquisition  of  a  greater 
quantity  of  oxygen  leads  to  a  greater  intensity  of  the 
process  of  assimilation,  and  consequently  to  a  gain  in  the 
weight  of  the  body. 

II. 

Exercise  produces  then  salutary  effects  alike  in  those 
who  assimilate  too  little  and  in  those  who  do  not  dis- 
similate  enough  ;  muscular  work  is  a  regulator  of 
nutrition  as  indispensable  to  over-rich  as  it  is  to  im- 
poverished constitutions.  Hence  there  is  no  individual, 
no  living  being,  who  is  not  instinctively  impelled  to  this 
powerful  general  alterative  agent. 

When  a  vigorous  horse  has  been  kept  in  the  stable 
for  a  long  time,  we  see  it  when  first  brought  out  make 
leaps  and  turns,  and  show  by  its  lively  paces  a  great 
desire  for  movement.  W^e  then  say  that  the  animal  is 
frisky.  This  great  vivacity  has  not  however  as  its  sole 
object  the  manifestation  of  the  joy  it  feels  at  being  again 
at  liberty  :  it  expresses  the  need  for  exercise  which  the 
animal  feels.  Similarly  it  is  under  the  influence  of  the 
need  for  exercise  that  the  wild  beasts  in   a  menagerie 

•  Experiments  of  Brown- Séquard. 


200  PHYSIOLOGY    OF    BODILY    EXERCISE. 

constantly  prowl  about  their  cages  ;  that  children  coming 
out  of  the  class-room  leap  and  run  about  the  recreation 
ground,  and  that  dogs  run  after  each  other  in  the  streets. 

Every  living  being  which  has  long  been  motionless  ex- 
periences a  need  for  action,  and  this  fact  is  alone  sufficient 
to  prove  the  hygienic  importance  of  muscular  exercise. 

The  7ieed  for  exercise  is  one  of  the  numerous  sensations 
which  lead  living  beings  to  perform  actions  necessary  for 
the  preservation  of  life  or  of  health.  Prolonged  immo- 
bility produces  a  need  for  muscular  exercise,  just  as  sus- 
tained work  produces  a  need  for  repose.* 

The  need  for  repose  is  called  fatigue  ;  the  need  for 
exercise  has  not  received  a  special  name,  but  deserves 
one  quite  as  much  as  hunger,  tlm^st,  etc. 

Under  the  influence  of  deficient  exercise,  certain 
materials  which  should  be  used  up  each  day  by  work, 
accumulate  in  the  human  machine,  the  wheels  of  which 
they  encumber,  and  the  v/orking  of  which  they  clog. 
These  materials  are  the  reserves  of  which  we  have 
pointed  out  the  origin  and  destination.  It  is  necessary, 
for  the  perfect  balance  of  nutrition,  that  the  reserve 
materials  should  be  used  up  as  fast  as  they  are  formed. 
When  they  are  not  regularly  destroyed  and  they  tend 
to  hinder,  by  their  accumulation,  the  working  of  the 
organs,  we  feel  ourselves  impelled  to  bring  our  muscles 
into  action,  with  the  unconscious  object  of  burning  these 
materials  in  the  work,  and  the  need  for  exercise  is 
produced. 

But  the  superabundance  of  the  reserve  materials  is 
not  the  only  cause  of  the  need  for  exercise;  if  insufficient 
exercise  can  lead  to  the  accumulation  of  certain  useless 
materials  within  the  system,  it  also  induces  a  diminution 
of  the  materials  necessary  to  the  balance  of  health,  and 
thus  leads  to  impoverishment  of  the  constitution  ;  so  we 
see  some  persons  whose  life  is  too  inactive,  put  on  too 

■*  The  need  for  exercise  is  developed  with  more  intensity  in  pro- 
portion to  the  lowness  of  the  temperature  ;  by  severe  and  piercing 
cold  we  are  much  more  driven  to  action  than  by  great  heat.  In 
this  case  the  need  for  exercise  is  derived  from  the  instinct  which 
leads  us  to  produce  heat  by  movement. 


GENERAL    EFFECTS    OF    EXERCISE.  291 

much  fat  and  become  plethoric,  whilst  others  waste  and 
become  thin  through  insufficient  movement. 

Thus  the  need  for  exercise  is  felt  as  much  by  thin 
people  who  assimilate  too  little,  as  by  fat  people  who  do 
not  dissimilate  enough. 

The  need  for  exercise  then  responds  to  two  physio- 
logical  necessities,  of  which  instinct  mves  us  warning-. 
It  can  come  from  an  overcharge  with  reserve  materials, 
and  the  urgent  necessity  there  is  that  these  materials 
should  be  burned  ;  it  may  also  arise  from  a  general  slug- 
gishness of  the  functions  and  the  need  of  a  stimulus 
capable  of  arousing  them  to  fresh  activity. 

The  need  for  burning  toi  abundant  reserves,  the  need 
for  drav/ing  more  oxygen  into  the  systen,  these  are  the 
two  causes  which  join  in  producing  the  manifestation  of 
the  instinct  which  leads  every  living  being  to  perform 
muscular  work.  But  if  the  useful  warning  is  misunder- 
stood, if  the  need  for  exercise  is  neglected,  two  orders 
of  phenomena  occur. 

In  the  first  place  the  quantity  of  oxygen  introduced 
into  the  system  being  insufficient,  the  blood  becomes 
less  rich,  less  vivifying  ;  its  contact  does  not  give  to  the 
organs  that  precious  stimulation,  that  salutary  whipping, 
which  makes  their  working  more  active  and  brings  all 
their  energy  into  play.  The  appetite  fails  through 
deficient  stimulation  of  the  digestive  organs,  through 
paresis  of  the  stomach  and  intestines.  The  muscles  lose 
their  irritability,  and  respond  more  slowly  to  the  stimulus 
of  the  will.  In  a  word,  all  the  functions  languish  and  the 
organism  becomes  weaker. 

On  the  other  hand,  the  reserve  materials,  not  being 
regularly  burned,  gradually  accumulate,  and  their 
presence  in  excess  in  the  system  leads  in  the  end  to 
serious  disturbances  of  health.  There  is  nothing  more 
frequent  in  persons  of  sedentary  habits  than  diseases 
brought  about  by  accumulation  of  these  reserve  ma- 
terials. Defective  dissimilation  of  fat  produces  Obesity  ; 
insufficient  combustion  of  the  nitrogenous  materials 
leads  to  Gout, 


292  PHYSIOLOGY    OF    BODILY    EXERCISE. 

These  two  disorders  are  not  exclusively  confined  to 
the  human  species.  Every  one  must  have  noticed  how 
domestic  animals,  under  the  influence  of  deficient  exer- 
cise, tend  to  grow  fat  ;  it  is  not  perhaps  as  generally 
known  that  inaction  may  make  them  gouty.  Larks  kept 
in  a  cage  often  show  on  their  feet  deposits  of  uric  acid 
exactly  like  the  "  tophi  "  seen  in  men  subject  to  gout. 

We  know  that  life  is  an  incessant  combustion,  and 
that  vital  heat  results  from  continual  chemical  combina- 
tions. The  air  drawn  into  the  lungs  leaves  its  oxygen 
in  the  blood,  and  this  is  the  chief  if  not  the  sole  agent 
of  the  combustions.  The  combustions  do  not,  as 
Lavoisier  believed,  occur  in  the  lungs  themselves,  but  in 
the  very  heart  of  the  tissues.  It  is  necessary  then  that  the 
oxygen  should  constantly  be  carried  to  the  combustible 
substances.  And  this  gas  is  carried  by  the  blood  to  the 
furthest  ramifications  of  the  circulatory  network. 

When  an  insufficient  quantity  of  oxygen  is  supplied 
by  respiration,  the  combustions  are  slow  and  incomplete, 
like  those  in  a  fire-place  in  which  the  draught  is  too 
feeble.  If  the  fire  languishes  in  a  fire-place  which  draws 
badly,  it  is  because  it  is  supplied  with  less  oxygen  owing 
to  the  slowness  of  the  air-current  passing  through  it. 
Thus  in  the  human  body  the  lungs  represent  the  fire- 
place, which  supplies  oxygen  to  the  tissues,  to  be  burned. 
If  insufficient  exercise  be  taken,  respiration  introduces 
too  small  a  supply  of  oxygen  into  the  system,  and  the 
vital  combustions  languish. 

From  the  insufficient  supply  of  oxygen  results 
incomplete  oxidation  of  the  substances  to  be  dissimilated. 
The  nitrogenous  tissues,  for  instance,  instead  of  being 
completely  burned  to  form  urea^  a  product  very  rich  in 
oxygen,  are  transformed  into  uric  acid  compounds, 
which  are  much  less  oxygenated.  Now  urea  is  a  very 
soluble  substance  and  is  easily  eliminated,  and  is  more- 
over almost  harmless  to  the  system.  Uric  acid  on  the 
contrary  is  sparingly  soluble,  and  consequently  is  elimi- 
nated with  great  difficulty  ;  if  it  is  formed  in  the  blood 
in  excessive  quantity  it  is  not  completely  eliminated  ; 
the  kidneys  which  should  remove  it  from  the  body  ieave 


GENERAL    EFFECTS    OF    EXERCISE.  293 

too  much  of  it  in  the  blood,  and  a  tendency  to  Gout  is 
developed.  Gout  in  fact  is  nothing  but  an  overcharge  of 
the  blood  with  uric  acid.  Very  various  accidents  may 
result  from  the  saturation  of  the  system  with  this  nitro- 
genous compound  which  we  might  call  the  "gouty 
poison."  When  it  is  deposited  in  the  joints  it  gives  rise 
to  an  attack  of  gout  ;  when  it  chokes  up  the  eliminating 
tubes  of  the  kidney  it  produces  Gravel. 

It  is  beyond  the  scope  of  this  book  to  give  a  com- 
plete account  of  the  diseases  which  arise  from  defective 
combustion.  But  it  was  necessary  to  take  an  example 
from  the  more  common  facts  of  pathology  in  order  that 
we  might  make  clear  the  mechanism  by  which  deficient 
exercise  produces  disease. 

III. 

To  get  an  exact  idea  of  the  effects  of  muscular  work 
on  the  general  process  of  nutrition,  it  is  enough  to  know 
the  opposite  effects  of  insufficient  exercise.  Now  we 
have  seen  that  the  results  of  insufficient  exercise  may 
be  reduced  to  two;  (i)  excessive  accumulation  of  re- 
serve materials  ;  (2)  insufficient  supply  of  oxygen.  K\\ 
the  morbid  conditions,  slight  or  severe,  due  to  deficient 
muscular  work,  are  derived  from  these  tv.^o  essential  dis- 
turbances in  the  balance  of  the  system. 

Want  of  oxygen  produces  a  languor  of  all  the  vital 
functions  by  defective  stimulation  of  the  organs  ;  hence 
insufficient  assimilation  of  food  and  enfeeblement  of  the 
system.  The  superabundance  of  reserve  materials 
leads  to  all  the  disturbances  of  health  due  to  insufficient 
dissimilation,  to  sluggish  nutrition.* 

Exercise  is  of  great  importance  as  a  regulator  of 
nutrition.  It  is  indispensable  to  the  maintenance  of 
health  to  heed  the  warning  given  to  us  by  the  system 
when  it  suffers  from  prolonged  inaction,  and  to  satisfy 
this  need  for  exercise  which  induces  every  living  being  to 
put  its  muscles  in  action. 

But    it   is   very   necessary  to    yield    promptly  to   the 

*  See  Professor  Bouchard's  book — "  Le  Ralentissement  de  la 
Nutrition." 


204  PHYSIOLOGY    OF    BODILY    EXERCISE. 

solicitations  of  this  instinct,  for  the  sense  of  need  for 
exercise  tends  very  soon  to  disappear  when  its  satisfac- 
tion is  delayed.  If  not  heeded  it  lessens  day  by  day;  if 
inaction  is  immoderately  prolonged,  it  disappears  en- 
tirely, and  a  time  arrives  when  the  organism  which  has 
too  long  led  an  inactive  life  shows  a  marked  tendency 
to  become  more  and  more  inactive.  This  is  because  too 
prolonged  repose  has  brought  about  new  organic  con- 
ditions, uniting  as  it  does  all  the  circumstances  which 
lead  to  the  production  of  every  kind  of  fatigue  when 
work  is  attempted. 

On  the  one  hand,  all  the  organs  languish,  and  cannot 
be  aroused  from  their  torpor  without  a  painful  effort  of 
the  will  ;  the  muscles  are  benumbed  and  but  little 
irritable  ;  the  heart,  which  rarely  undergoes  the  agitations 
of  exercise,  is  too  impressionable,  like  all  enfeebled 
organs,  and  the  slightest  muscular  exertion  causes- 
palpitation  ;  the  lungs,  accustomed  to  the  respiratory 
movements  suitable  to  the  inconsiderable  needs  of  an 
inactive  life,  have  long  been  used  to  bring  into  action 
only  a  small  proportion  of  their  air-cells,  the  others  being 
closed  and  collapsed  during  the  respiratory  act.  The 
field  for  aeration  of  the  blood  being  in  this  manner  reduced, 
the  slightest  increase  in  the  activity  of  the  gaseous 
interchange  renders  the  respiratory  functions  insufficient. 

On  the  other  hand,  prolonged  inaction  predisposes  the 
body  to  a  ready  intoxication  after  work,  owing  to  the 
abundance  of  the  re^.erve  materials,  a  source  of  products 
of  dissimilation  and  waste.  When  a  fat  man  undertakes 
violent  exercise,  his  fatty  tissues  undergo  violent  com- 
bustions, which  are  more  exaggerated  in  proportion  to 
the  urgency  and  duration  of  the  need  for  their  dissimila- 
tion. These  tissues,  very  rich  in  carbon,  give  rise  to  an 
abundant  formation  of  carbonic  acid,  and  breathless- 
ness  occurs  with  exaggerated  intensity.  If  the  man, 
instead  of  being  fat,  has  in  his  body -a  great  quantity  of 
nitrogenous  reserves,  breathlessness  will  not  be  the 
dominant  feature,  and  immediate  fatigue  will  be  but 
moderate  ;  but  consecutive  fatigue  will  be  extreme. 
We   have    described    all    the    disturbances   which    arise 


CFNERAL    EFFECTS    OF    EXERCISE.  295 

from  intoxication  by  the  rroducts  of  nitrogenous  waste, 
and  have  shown  that  stiffness  is  in  direct  proportion  to 
the  quantity  of  these  waste-products.  Hence  consecu- 
tive fatig"ue  is  to  be  feared  by  a  man  too  rich  in  reserve 
materials,  he  has  further  to  fear  lest  fatiq-ue  should  pro- 
voke an  attack  of  gout  by  producing  a  regular 
f  vakmche  of  uric  acid  compounds. 

Thus  it  is  that  after  too  prolonged  inaction,  exercise, 
instead  of  being  accompanied  by  a  sensation  of  satis- 
faction, becomes  a  painful  toil.  The  man  unused  to 
work  foresees  that  a  disagreeable  physical  sensation  will 
attend  the  throwing  off  of  his  inertia  ;  he  "  fears  fatigue." 
Hence  he  finds  himself  caught  in  a  vicious  circle  from 
which  he  cannot  free  himself.  He  acts  no  longer, 
because  his  organs,  loaded  by  the  accum^ulation  of 
reserve  materials,  make  work  painful  to  him,  and  the 
accumulation  becomes  greater  the  longer  he  remains 
inactive.  If  he  has  not  the  courage  to  submit  to  the 
inevitable  pain  which  accompanies  every  beginning  of 
physical  exercises,  if  he  shuts  himself  up  in  his  inaction, 
to  which  the  presentiment  he  has  of  the  discomTorts  of 
fatigue  more  and  more  inclines  him,  his  condition  be- 
comes aggravated,  and  he  inevitably  falls  into  a  state 
characterised  either  by  an  excessive  richness  of  reserve 
materials,  or  by  impoverishment  of  the  system  and 
languor  of  the  vital  functions. 

Thus  the  sense  of  need  for  exercise  corresponds  to 
different  organic  conditions,  to  diametrically  opposed 
organic  states. 

The  general  effects  of  exercise  tend  to  modify  all  con- 
stitutions in  a  sense  favourable  to  that  perfect  equili- 
brium of  the  functions  which  constitutes  health.  By  the 
mere  fact  of  the  adaptation  of  the  organs  to  the  varied 
needs  of  muscular  exercise,  the  irregularities  of  nutrition 
tend  to  disappear.  By  the  very  fact  of  regular  perform- 
ance of  function,  the  Human  Machine  becomes  more 
fitted  to  perform  its  functions  well,  and  gains  the  con- 
formation best  adapted  for  the  performance  of  work  ; 
now  this  conformation  is  also  that  which  is  most  favour- 
able to  the  regular  performance  of  all  vital  actions. 


29(5.  PHYSIOLOGY    OF    BODILY    EXERCISE. 

Thus  it  is  that  muscular  movement  is  useful  in  all 
disorders  of  nutrition,  and  that  bodily  exercise  is  a 
necessity  for  all  constitutions. 

But  we  must  not  conclude  that  the  benefit  of  exercise 
is  equal  in  all  cases,  whatever  may  be  the  quality  of  the 
work  done.  If  muscular  movement  produces  a  series  of 
identical  general  effects  in  all  constitutions,  the  different 
exercises  we  have  considered  in  the  fourth  part  of  this 
book  have  all  of  them  their  special  effects. 

We  cannot  enter  here  into  details  of  application,  and 
reserve  for  another  volume  the  complete  study  of  the 
Therapeutics  of  Exercise.  It  will  be  enough  to  recall,  in 
finishing  this  chapter,  how  the  special  effects  of  exercise 
may  vary  according  to  its  kind  and  its  dosage. 

We  have  seen  that  work  has  two  opposite  influences  on 
nutrition  ;  it  increases  the  gains,  and  it  also  increases 
the  losses  of  the  system.  The  hygiene  of  work  essentially 
consists  in  balancing  these  two  opposed  results  ;  but 
certain  conditions  of  exercise  may  make  now  one,  now 
the  other,  predominate,  and  it  is  possible  to  obtain 
almost  at  will,  by  the  aid  of  muscular  work,  either  an 
increase  or  a  diminution  in  the  weight  of  the  body. 

An  example  borrowed  from  Dr.  Worthington's  book 
on  "  Obesity  "  will  suffice  to  show  how  work  can  lead, 
according  to  the  details  of  its  application,  to  diametrically 
opposed  results.  On  the  Marne,  between  Aifort  and 
Chateau-Thierry,  two  teams  of  horses  worked  on  a 
towing  path,  drawing  boats.  The  first  team  drew  up 
stream,  walking  \  the  second  down  stream,  but  trotting. 
This  course  was,  for  each  team,  the  only  work  of  the 
day.  As  far  as  the  quantity  of  work  done  each  day 
was  concerned,  the  horses  which  walked  executed  a 
greater  number  of  kilogrammetres,  since  they  went  the 
same  distance,  but  against  the  current  ;  the  horses 
coming  down  stream  drew  a  lighter  load  and  covered 
the  same  distance  ;  but,  in  spite  of  the  difference  in  the 
quantity  of  the  work,  the  swiftness  of  their  pace  com- 
pletely changed  for  them  the  results  of  the  work  ;  the 
horses  which  did  their  work  at  a  trot  got  thinner,  those 
which  walked,  gained  weight. 


CHAPTER  IL 

EXERCISES   WHICH   DEVELOP   THE   CHEST. 

Importance  of  Oxygen  in  NutritioTi — Advantages  of  a  groat 
Development  of  the  Chest — How  this  Result  can  be  obtained 
by  Exercise — Received  Opinions  on  this  Subject — Our  Reasons 
against  them — By  what  Mechanism  the  Chest  is  Developed — 
Forced  Breathing — Pressure  from  within  outwards — Increased 
Breadth  of  the  Shoulders  not  to  be  Confused  with  Increased 
Size  of  the  Chest — Conditions  which  Develop  the  Chest — Am- 
plitude of  the  Respiratory  Movements — Opening  out  of  the 
Pulmonary  Air-cells — 'Increase  of  the  Respiratory  Need — The 
Chest  of  Mountaineers — Exercises  which  produce  a  "  Thirst  for 
Air"  —  Exercises  suitable  for  Developing  the  Chest — An  un- 
expected conclusion  :  Superiority  of  Exercises  of  the  Legs  to 
those  of  the  Arms — Running  and  Skipping. 

I. 

The  quantity  of  air  introduced  into  the  system  at  each 
respiration  is  regulated  by  the  capacity  of  the  lungs. 
Now  we  have  seen  in  the  preceding  chapter  that  the 
acquisition  of  a  great  quantity  of  oxygen  is  one  of  the 
most  useful  results  of  bodily  exercises. 

It  is  then  of  great  importance  to  define  the  conditions 
in  which  muscular  work  is  capable  of  increasing  the  size 
of  the  cavity  in  which  the  lungs  are  contained. 

At  first  sight  we  should  be  inclined  to  believe  that  the 
exercises  performed  with  the  upper  limbs,  which  are 
moved  by  the  muscles  of  the  shoulders  and  trunk,  to  be 
those  most  likely  to  raise  the  ribs  ;  and  in  fact  exercises 
of  the  arms  are  generally  regarded  as  excellent  for  in- 
creasing the  respiratory  power. 

It  will  be  enough  to  quote  and  criticise  a  very  con- 
scientious study  by  Demény,*  to  show  the  fallacy  of 
this  opinion. 

*  Georges  Deménv.     De  l'Education  Physique. 


298  PHYSIOLOGY  OF  BODILY    EXERCISE. 

"  We  have  determined,"  says  this  author,  "  that  there 
are  various  degrees  of  exercise  favourable  to  the  dilation 
of  the  thorax. 

"  The  attitudes  in  which  the  scapulae,  drawn  back  and 
fixed  by  the  tonicity  and  by  the  contraction  of  the  rhom- 
boidei,  trapezia,  and  latissimi  dorsi  muscles,  serve  as  fixed 
points  for  the  elevators  of  the  ribs,  these  attitudes,  of  which 
the  type  is  the  soldier  at  attention,  the  body  upright,  the 
belly  retracted  by  the  aspiration  of  the  thoracic  viscera^ 
produce  a  manifest  dilation  of  the  thorax. 

"  Still  more  a  slight  backward  motion  of  the  arms, 
rotation  outwards,  abduction,  and  most  of  all  the  vertical 
elevation  of  the  arms,  as  in  passive  suspension  with  the 
arms  at  full  length,  raise  the  ribs  to  a  maximum  degree, 
and  give  to  the  costal  cartilages  a  mobility  which  allows 
of  great  inspiratory  movements,  and  opposes  the  fixation 
of  the  thorax, in  the  position  of  expiration." 

These  conclusions  are  preceded  -  by  very  interesting 
considerations  on  the  muscles  which  are  brought  into 
action  in  these  attitudes,  and  the  author  clearly  demon- 
strates that  inspiratory  muscles  are  brought  into  action. 
Their  two  extremities  are  separated  in  these  attitudes, 
and  the  muscular  tone  tends  to  draw  the  movable  points 
of  attachment,  represented  by  the  ribs,  nearer  to  the 
fixed  points  of  attachment  represented  by  the  scapula, 
the  clavicle  and  the  humerus. 

Demeny's  conclusion  is  that  more  air  enters  the  chest 
in  the  attitudes  he  describes,  than  in  the  condition  of 
repose.  It  is  certain  that  in  these  attitudes  the  ribs  are 
very  strongly  raised,  but  the  author  condemns  himself 
by  remarking  that  the  thoracic  aspiration  draws  up  the 
abdominal  viscera  under  cover  of  the  ribs,  so  that  the 
diaphragm  is  thrust  upwards. 

If  v/e  try  to  define  the  respiratory  advantages  gained 
by  this  manoeuvre,  we  see  that  it  puts  into  forced  action 
all  the  inspiratory  muscles  except  the  diapJiragm,  whicli 
remains  in  the  position  of  expiration,  for  it  is  pushed  up 
by  the  abdominal  viscera.  Now  if  a  man,  keeping  his 
hands  in  his  pockets,  takes  the  trouble  to  take  a  ve^y 
deep  inspiration,  he  will  be  able  to  raise  his  ribs  to  the 


EXERCISES  WHICH   DEVELOP  THE   CHEST.        299 

greatest  possible  limits,  and  further,  he  will  find  that  his 
diaphragm  will  share  in  the  movement,  and  will  push 
down  the  abdominal  viscera^  instead  of  allowing  itself  to 
be  thrust  up  by  them  into  the  chest.  The  vertical 
diameter  of  the  thorax  will  thus  be  increased,  while 
before  it  was  diminished  hy  visceral  aspiration^  and  in 
ib.e  end,  it  will  be  found  that  the  most  ingenious 
gymnastic  combinations  are  not  as  efficient  in  increasing 
the  intra-thoracic  space  as  are  profound  expirations 
made  during  repose. 

The  conclusion  from  this  is,  that  the  best  athletic 
exercise  for  increasing  the  size  of  the  chest  is  that  which 
"compels  the  deepest  inspirations. 

Before  developing  this  idea  we  must  explain  the 
mechanism  in  virtue  of  which  a  temporary  amplification 
of  the  thorax  can  in  a  short  time  produce  a  lasting 
increase  in  its  capacity.  But  we  must  first  remark  that 
it  is  of  no  advantage  in  respiration  to  increase  the 
thickness  of  the  thoracic  parietes,  if  the  cavity  remains 
small  ;  it  is  the  intra-thoracic  space  which  must  be 
amplified  in  order  to  increase  the  respiratory  power. 

Now  there  is  only  one  way  of  increasing  this  space, 
and  that  is  to  increase  the  volume  of  its  contents,  the 
lungs. 

It  would  be  illusory  to  set  any  value  on  the  elevation 
of  the  ribs,  on  a  favourable  direction  of  the  costal 
articulations,  on  the  strength  of  the  inspiratory  muscles, 
etc.,  if  the  lungs  were  not  increased  in  size  at  the  same 
time  as  the  thoracic  cavity  is  dilated.  If  the  lungs 
become  weakened,  the  upper  ribs  fall  in,  and  the  best 
formed  chest  becomes  flat.  An  empty  thoracic  cavity  is 
incompatible  with  raised  ribs,  and  do  what  we  will  an 
empty  chest  assumes  the  position  of  inspiration. 

We  see  this  every  day  after  the  absorption  of  pleuritic 
effusions,  when  the  lung  tied  down  by  false  membranes 
is  incapable  of  returning  to  its  normal  size,  and  perhaps 
is  reduced  in  volume  by  one  half  or  two  thirds.  How- 
ever powerful  the  inspiratory  m»"scles,  whatever  the 
direction  of  the  costal  articulations,  the  ribs  cannot  be 
raised,  for  a  vacuum  cannot  exist  in  the  pleural  cavity. 


300  PHYSIOLOGY    OF    BODILY    EXERCISE. 

Thus,  in  the  thorax,  the  volume  of  the  receptacle  is 
determined  by  the  size  of  the  contents.  If  you  wish  to 
develop  the  chest,  do  not  try  to  raise  the  ribs,  but  try  to 
inflate  all  the  air-cells  of  the  lungs  ;  you  cannot  do  it  by 
any  mechanical  means,  and  the  most  clever  combinations 
of  muscular  movements  give  but  an  incomplete  result 
when  unaccompanied  by  the  movement — voluntary  or 
instinctive — of  forced  inspiration. 

The  experiments  of  M.  Demény  certainly  prove  that 
the  gymnastic  attitudes  he  describes  are  the  most 
efficient  in  raising  the  ribs  ;  but  they  also  prove  that  the 
raising  of  the  ribs,  carried  to  an  extreme,  does  not 
suffice  to  give  a  maximum  size  to  the  lungs,'for  when 
the  ribs  are  raised,  the  diaphragm  goes  deeper  into  the 
thorax  and  the  abdominal  viscera  rise.  The  respiratory 
field  thus  loses  at  the  base  of  the  chest  what  it  gains  at 
the  apex. 

The  momentary  amplification  of  the  thorax  during 
inspiration  may  indeed  lead  to  energetic  contraction  of 
the  inspiratory  muscles  ;  but  a  definite  increase  in  size, 
persisting  during  repose,  can  only  be  brought  about 
through  increased  volume  of  the  lungs. 

How  is  it  that  the  lungs  can  increase  in  size  through 
athletic  exercise  ?  By  a  mechanism  well  known  in 
physiology,  by  the  filling  out  of  certain  air-cells 
ordinarily  inactive,  which  only  come  into  play  during 
forced  inspiration.  The  expansion  of  the  pulmonary 
vesicles  is  complete  in  proportion  to  the  quantity  of  air 
introduced.  The  atmospheric  air  drawn  into  the  lungs 
by  a  very  powerful  inspiration  seeks  out  the  most 
obscure  corners,  and  inflates  the  air-cells  of  certain 
regions  which  ordinarily  have  no  part  in  the  respiratory 
function. 

A  definite  increase  in  the  volume  of  the  lungs  is  the 
consequence  of  frequent  repetition  of  this  supplemental 
respiration.  The  air-cells  which  are  as  a  rule  inactive, 
and  which  are  reserved  for  cases  of  excessive  respirato  y 
strain,  arise  from  their  inaction  ;  their  walls,  which  are 
usually  collapsed,  and  even  stuck  together,  separate  and 


EXERCISES    WHICH    DEVELOP    THE    CHEST.      3OI 

mve  entrance  to  the  air  which  cannot  find  room  in  the 
confined  space  sufficient  for  ordinary  breathing". 

If  the  forced  inspirations  are  often  repeated,  the  air- 
cells,  the  action  of  which  has  thus  been  accidentally 
solicited,  come  in  the  end  to  associate  regularly  in  the 
ordinary  respiratory  movements.  They  are  then  very 
quickly  modified  in  the  sense  most  favourable  for 
efficient  working,  according  to  the  law  we  have  so  often 
pointed  out,  of  the  adaptation  of  organs  to  the  functions 

they  perform.  . 

Thus,  forced  respirations  result  in  a  modification  ot 
the  structure  of  certain  regions  of  the  lung,  and  in 
making  them  work  better.  Under  the  influence  of 
unusual  exercise  the  vesicles  increase  in  size  and  contain 
more  air.^  More  blood  is  also  supplied  to  them.  Their 
capillary  network  becom.es  richer,  and  their  nutrition 
more  active.    Thus  in  the  end  they  take  up  more  room. 

It  is  in  this  manner  that  the  regular  working  of  a 
great  number  of  air-cells,  ordinarily  inactive,  can  rapidly 
increase  the  size  of  the  lungs.  ,  ,      r        j 

If  we  follow  out  the  modifications  produced  by  forced 
respirations,  we  see  that  the  lungs  thrust  outwards  the 
thoracic  walls  to  make  more  room  for  themselves. 
During  inspiration  the  ribs,  by  rising,  favour  the 
inflation  of  the  lungs,  but  in  this  case  it  is  the  lungs 
which,  having  increased  in  size,  thrust  the  ribs  upwards 
and  keep  them  raised  even  in  the  condition  of  repose. 
Hence  an  increase  in  the  circumference,  and  a  vaulted 
conformation  of  the  thorax. 

It  is  th&nfrom  zvitJim  outwards  that  the  force  capable 
of  expanding  the  chest  acts,  and  it  is  in  reality  to  the 
lungs  and  not  to  the  muscles  that  the  chief  share  in 
the  changes  in  form  and  size  of  the  chest  belong.  The 
most  powerful  inspiratory  muscles  cannot  raise  the 
ribs,  unless  the  lungs  participate  in  the  movement  of 
expansion,  and  on  the  other  hand,  the  lungs  can  raise 
the  ribs  without  the  aid  of  the  muscles,  for  the  chests  of 
emphysematous  patients  remain  vaulted  in  spite  of  their 
efforts  to  lower  the  ribs  and  complete  the  expiratory 
movement 

21 


302  PHYSIOLOGY    OF    BODILY    EXERCISE. 

If  we  sum  up  the  facts  we  have  just  enunciated^  we 
shall  be  driven  to  the  conclusion  that,  in  order  to  raise 
the  ribs  and  get  rid  of  the  vicious  conformation  of  flat 
chest,  we  must  not  seek  to  act  directly  on  the  thoracic 
muscles,  but  to  produce  as  extensive  respiratory  move- 
ments as  possible. 

There  are  two  methods  of  amplifying  respiration  ;  one 
consists  in  voluntarily  expanding  the  thorax  in  all  direc- 
tions. This  method  is  in  the  domain  of  "  chamber-gym- 
nastics"; it  has  been  much  extolled,  and  it  may  give  good 
results.  The  other  method  comes  more  directly  into  the 
field  of  our  studies.  It  consists  in  increasing  by  exercise 
the  amplitude  of  the  respiratory  movements. 

II. 

The  problem  has  now  become  clear  and  definite.  We 
need,  in  order  to  develop  the  chest,  to  know  what  exercises 
are  most  fitted  to  produce  a  series  of  very  extensive  res- 
piratory movements.  Now  the  amplitude  of  respiration, 
as  well  as  its  frequency,  is  in  direct  ratio  to  the  intensity 
of  the  respiratory  need,  and  we  know  that  the  intensity  of 
this  need  depends  on  the  quantity  of  mechanical  work 
performed  in  a  given  time.* 

The  exercises  which  cause  an  accumulation  of  work  are 
then  those  most  fitted  for  increasing  the  size  of  the  thorax, 
and  for  demanding  increased  work  from  the  lungs.  And 
we  know  that  this  accumulation  of  work  occurs  especially 
in  exercises  of  strength  and  speed. 

Thus  the  mechanism  of  exercise,  its  performance  by 
the  aid  of  these  muscles  or  of  those,  are  of  secondary  im- 
portance in  producing  the  result  of  which  we  are  speaking. 
It  matters  little  by  what  process  the  muscular  force  is 
expended,  provided  that  there  is  great  expenditure  in  a 
short  period  of  time.  It  is  indifferent  whether  the  move- 
ments are  very  slow,  each  of  them  representing  a  great 
number  of  kilogrammetres,  or  whether  they  are  extremely 
rapid,  each  movement  representing  but  a  moderate  effort 
It  is  merely  necessary  that  the  sum  of  work  represented 

♦  See  Chapter  IV.     "  Breathlessnerss." 


EXERCISES    WHICH    DEVELOP    THE    CHEST.      303 

by  these  movements,  whether  few  or  many,  should  be 
considerable  in  a  short  time. 

Now  the  quantity  of  work  which  a  given  muscular 
group  can  perform  in  a  given  time  is  subordinated  to  the 
strength  cf  this  group.  There  are  muscular  groups  which 
are  too  weak  to  expend  much  force  in  a  short  time.  One 
arm  may  use  its  whole  strength  without  its  work  repre- 
senting, in  the  unit  of  time,  a  great  number  of  kilogram - 
metres.  vSo  whatever  form  the  exercise  takes,  if  the  arm 
alone  is  working,  we  shall  not  find  that  the  breathing  is 
much  quickened.  The  exercise  may  induce  local  fatigue 
before  the  intensity  of  the  respiratory  need  has  increased. 
It  may  even  happen  that  the  work  of  both  arms  together 
does  not,  after  a  given  time,  amount  to  enough  to  demand 
more  ample  respirations. 

In  general,  the  exercises  which  are  performed  with  the 
legs  represent  more  work  than  those  which  are  performed 
with  the  arms.  The  muscles  of  the  upper  limbs  could 
not  support,  without  extreme  fatigue,  an  expenditure  of 
force  which  will  cause  no  effort  to  the  lower  limbs.  It 
is  not  tiring  to  anyone  to  walk  500  metres-  in  five 
minutes  :  what  gymnast  could  traverse  the  same  distance 
in  the  same  time  hanging  by  his  hands  from  a  stretched 
rope  ?  The  total  mechanical  work  would  be,  however, 
the  same  ;  displacing  the  same  weight  through  the  same 
horizontal  distance. 

We  must  not  then  trust  to  the  muscles  of  the  arms  to 
expand  the  chest.  Muscular  exercise  can  only  lead  to 
the  development  of  the  thorax  in  an  indirect  manner, 
and  in  no  way  by  a  direct  effect  comparable  to  the 
increase  in  size  of  a  muscle  which  works.  The  muscle 
which  contracts  often  becomes  larger  because  its  nutrition 
is  more  active.  But  the  chest  only  expands  when  the 
surcharge  of  the  blood  with  carbonic  acid  creates  a  need 
of  a  greater  quantity  of  oxygen  for  haematosis. 

It  is  to  the  more  active  respiratory  need,  to  the  "  thirst 
for  air,"  that  the  instinctive  movement  by  which  the  ribs 
are  more  energetically  raised  is  due,  in  order  to  draw  into 
the  lungs  a  greater  quantity  of  air. 

The  thirst  for  air,  carried  too  far,  produces  breathless- 


304  PHYSIOLOGY    OF    BODILY    EXERCISE. 

ness,  which  is  nothing  else  than  a  powerless  struggle  of 
the  system  seeking  in  vain  to  satisfy  a  need.  When 
breathlessness  is  very  moderate  it  causes  very  ample 
respiratory  movements  ;  but  when  it  is  excessive  the 
breathing  becomes  very  shallow  as  well  as  very  rapid. 

So  that  exercise  has  no  longer  any  effect  in  expanding 
the  chest,  when  breathlessness  reaches  an  extreme 
degree. 

To  sum  up,  the  most  profitable  way  of  dilating  the 
lungs,  developing  the  thorax  and  expanding  the  chest, 
consists  in  the  performance  of  exercises  capable  of  in- 
creasing the  respiratory  need,  without  pushing  them  so 
as  to  produce  an  extreme  degree  of  breathlessness. 

If  we  pass  from  physiological  explanation  to  observa- 
tion of  facts,  we  see  that  practice  gives  a  striking  con- 
firmation of  theory. 

Exercises  of  strength  lead  rapidly  to  an  increase  in 
the  size  of  the  thorax.  It  is  the  same  with  exercises  of 
speed  when  they  need  very  energetic  movements.  No 
exercise  develops  the  chest  as  rapidly  as  does  running, 
unless  it  be  wrestling. 

Mountaineers  all  have  large  chests,  and  the  Indians 
who  live  on  the  high  plateaux  of  the  Cordillera  in  the 
Andes,  have  been  noted  for  the  extraordinary  size  of 
their  chests. .  This  great  development  in  mountaineers  is 
due  to  two  causes  which  act  in  the  same  direction  : 
frequent  ascent  of  steep  inclines,  and  constant  residence 
at  great  heights  at  which  the  air  is  rarefied.  The  climb- 
ing of  these  slopes  needs  a  great  quantity  of  work,  which 
causes  increase  of  the  respiratory  need  ;  respiration  in  a 
rarefied  atmosphere  obliges  a  man  to  take  deeper  breaths 
in  order  to  supplement,  by  the  quantity  of  air  breathed, 
the  insufficiency  of  its  vivifying  properties. 

Singers,  with  no  other  exercise  but  singing,  acquire 
great  respiratory  power  and  a  remarkable  increase  in  the 
dimensions  of  their  chests. 

Numerous  observations  prove  that  it  is  enough  volun- 
tarily to  take  a  certain  number  of  deep  breaths  every 
day,  to  produce,  in  a  short  tim.e,  an  increase  in  the  cir- 


EXERCISES    WHICH    DEVELOP    THE    CHEST.      305 

cumferencc  of  the  chest  which  may  amount  to  two  or 
three  centimetres. 

If  we  wish  to  g3.m  the  same  result  from  muscular 
exercise,  we  must  choose  a  form  of  work  which  will 
increase  the  intensity  of  the  respiratory  effort,  that  is. 
an  exercise  which  brings  powerful  muscular  masses  into 
action.  We  shall  thus  perform  a  great  quantity  of  work 
in  a  short  time  without  producing  fatigue.  Now  the 
legs,  which  possess  three  times  as  much  muscle  as  the 
arms,  can  perform  thrice  the  quantity  of  work  before 
being  fatigued.  The  lower  limbs  are  then  more  capable 
than  the  arms  of  awakening  the  respiratory  need,  which 
is  proportional  to  the  expenditure  of  force. 

Thus  it  is  an  error  to  demand  from  gymnastic 
exercises  practised  with  appliances,  exercises  of 
suspension  or  support,  any  development  of  the  chest. 
The  trapeze,  the  rings,  the  parallel  bars,  quicken  respira- 
tion much  less  than  running.  These  exercises  cause  an 
increase  in  the  size  of  the  muscles,  and  even  of  the 
bones  of  the  regions  which  work,  but  they  cause  very 
little  increase  in  the  dimensions  of  the  thorax. 

Men  who  do  much  work  with  their  arms  have  often 
a  conformation  which  is  very  imposing  at  the  first 
glance.  They  have  sometimes  broad  shoulders  ;  but  if 
the  arms  have  done  the  work  alone,  without  the  assist- 
ance of  the  muscles  of  the  trunk,  we  easily  see  that  the 
apparently  large  size  of  the  thorax  is  due  to  an  exces- 
sive development  of  the  muscles  about  the  shoulder 
joint,  and  not  to  raising  of  the  ribs. 

Thus  we  are  on  the  wrong  road  when  we  look  for  too 
ingenious  means  for  developing  the  chest  ;  this  result, 
precious  above  all,  can  be  obtained  without  any  com- 
plicated appliances,  without  any  difficult  process,  and  if 
we  had  to  formulate  concise  advice  on  this  subject  we 
should  say  : — 

When  a  young  person  has  a  narrow  and  flat  chest, 
recommend  running  if  it  be  a  boy,  or  skipping  if  a  girl. 


CHAPTER   TIL 

LOCAL   EFFECTS   OF   EXERCISE. 

Effects  on  neighbouring  parts.  Useful  Effects:  Compression  of 
Vessels  by  the  Contracting  Muscles  ;  Quickening  of  the  Circula- 
tion as  a  result — Disappearance  of  Œdema  during  Exercise — 
Injurious  Effects  of  Muscular  Contraction  :  Excessive  Com- 
pression of  Internal  Organs — Dangers  of  Effort — Effects  of 
Work  on  Muscle — Useful  Effects  :  Increase  in  Size — Injurious 
Effects  ;  Wasting  of  the  Organ  through  Excessive  Work —  The 
Accidents  of  Work.  Muscular  Ruptures — Tendency  of  Muscular 
Fibre  to  Shorten  through  Excessive  Work — Semi-flexion  of  the 
Fore-arm  in  Gymnasts — Dangers  of  Muscular  Contract«res-r- 
How  Deviations  of  the  Spine  are  produced  by  lU-planned 
Exercise. 

Muscular  work  produces  local  effects  of  two  kinds. 
The  first  kind  occurs  in  the  muscles  themselves,  in  the 
bones  which  are  moved,  and  in  the  joints  which  are  the 
centres  of  movement.  The  second  occurs  throughout 
the  region  in  which  the  movement  takes  place,  and 
concerns  organs  which  take  no  direct  part  in  the 
exercise.  We  shall  study  separately  the  direct  effects 
of  muscular  contraction,  and  its  effects  on  neighbouring 
parts. 

I. 

The  chief  effects  observed  in  the  regions  which  are 
the  seat  of  repeated  muscular  movement  are  due  to  the 
compression  which  the  muscle,  in  becoming  shorter  and 
thicker,  exercises  on  neighbouring  parts.  This  com- 
pression may  either  affect  vessels  containing  fluids,  such 
as  the  lymph  and  the  blood,  or  more  solid  materials,  as 
the  intestinal  contents,  and  the  pressure  may  thus  be 
transmitted  to  remote  points.  Hence  result  effects  which 
are  not  strictly  localised,  and  which  serve  as  a  connecting 
link  between  the  local  and  the  general  effects  of  exercise. 


LOCAL    EFFECTS    OF    EXERCISE.  307 

In  this  manner  the  contraction  of  the  abdominal 
muscles  durint^  exercise  may  influence  the  digestive 
functions  by  driving  onwards  the  intestinal  contents. 
An  exercise  which  brings  the  abdominal  muscles  into 
action  is  thus  favourable  to  defalcation,  and  can  cause 
the  disappearance  of  digestive  disorders  due  to  con- 
stipation. 

Similarly,  the  compression  which  the  muscles  exercise 
on  the  capillary  vessels  gives  a  more  active  impulse  to 
the  blood-current,  which  is  transmitted  even  to  the 
heart,  just  as  pressure  on  an  india-rubber  tube  filkd 
with  water  is  transmitted  to  the  elastic  reservoir  with 
which  this  tube  communicates.  In  this  manner  the 
local  contraction  of  a  muscle  can  influence  the  general 
circulation.  We  know  that  stagnation  of  blood,  in 
motionless  limbs,  can  produce  œdematous  swelling,  and 
we  also  know  that  such  limbs  can  regain  their  normal 
size  under  the  influence  of  exercise  which  causes  con- 
traction of  the  muscles,  and  mechanical  acceleration  of 
the  blood-current  in  the  capillaries. 

The  effects  of  muscular  compression  on  the  neighbour- 
ing parts  are  not  always  useful  :  exaggerated  contraction 
can  lead  to  accidents.  Thus,  too  powerful  contraction 
of  the  abdominal  muscles  can  make  the  intestines,  by 
great- pressure,  distend  a  natural  orifice  and  become 
eno-aged  there.  It  is  thus  that  hernise  are  produced  in 
the  inguinal  or  crural  canal  through  the  passage  of  an 
intestinal  coil  subjected  to  too  great  pressure.  This 
accident  is  most  commonly  produced  during  the  act  of 
effort,  which  demands,  as  we  have  explained,  a  very 
energetic  contraction  of  the  abdominal  muscles.  ^ 

Still  more  serious  accidents  may  happen  during  very 
powerful  contraction.  An  essential  condition  of  effort 
is  the  compression  of  the  distended  lungs,  which  serve 
to  support  the  ribs.  An  energetic  compression,  pro- 
portionate to  the  intensity  of  the  muscular  work,  is 
exercised  during  the  effort  on  .the  great  thoracic  vessels 
and  even  on  the  heart.  It  may  happen  that  the  pressure 
exercised  on  the  vessels  is  sufficiently  strong  to  cause  a 
-  back  tide  of  blood  in  the  capillaries  of  the   lungs  or 


308  PHYSIOLOGY    OF    BODILY    EXERCISE. 

brain,  and  to  bring  about  laceration  of  these  vessels, 
and  pulmonary  or  cerebral  haemorrhage. 

Rupture  of  the  great  veins  of  the  spine  has  been 
observed  from  the  effect  of  too  violent  an  effort.  In  this 
case  there  occurs  a  hcTemorrhage  in  the  spinal  cord  which 
c'AM^ç^'à  paraplegia,  that  is  to  say,  paralysis  of  the  parts  of 
the  body  below  the  lesion.  We  may  frequently  see  a 
horse,  harnessed  to  too  heavy  a  cart,  give  an  energetic 
pull,  and  fall  with  its  hindquarters  paralysed.  Through 
too  violent  an  effort  the  animal  has  broken — not  its  back, 
as  is  commonly  said — but  a  vessel  in  the  spinal  cord,  and 
paraplegia  has  ensued. 

Ruptures  of  the  heart  have  even  been  recorded  in  con- 
sequence of  very  violent  efforts.  A  porter  at  Bordeaux 
had  made  a  wager  that  he  would  lift  a  full  hogshead.  In 
the  superhuman  effort  he  made  to  raise  this  enormous 
burthen,  his  heart  was  ruptured  and  he  dropped  down 
dead. 

These  mechanical  effects  of  exercise  are,  as  we  said 
above,  on  the  borderland  between  the  general  and  the 
local  effects  of  exercise.  We  are  now  going  to  describe 
those  which  are  strictly  local. 

II. 

Muscular  contraction  may  be  the  cause  of  useful 
effects,  and  may  also  occasion  accidents  and  various 
lesions.  Among  the  disagreeable  effects  of  exercise, 
some  are  the  inevitable  result  of  muscular  contraction  ; 
others  occur  accidentally,  either  through  a  vicious  method 
of  performing  the  work,  or  owing  to  defective  resistance 
in  the  organs  which  perform  it. 

Numerous  cases  have  been  recorded  of  rupture  of 
muscles  during  the  performance  of  muscular  actions. 
These  ruptures  are  always  produced  when  a  muscular 
fibre  contracts  with  an  energy  which  exceeds  its  own 
power  of  resistance.  They  are  often  the  consequence  of  a 
badly  co-ordinated  movement.  If,  for  instance,  only  one 
muscle  is  employed  in  the  performance  of  an  action  for 
which  a  muscular  group  is  needed,  it  will  break  just  as  a 
cord  breaks  when  employed  to  lift  a  weight  which  is  too 


LOCAL    EFFECTS    OF    EXERCISE.  309 

heavy  for  it.  Or  the  defective  co-ordination  consists  in 
this,  that  the  part  to  be  moved  is  soHcited  by  a  sudden 
effort  to  pass  from  immobility  to  motion,  instead  of 
doing-  so  gradually.  Thus  unforeseen  movements  are  a 
frequent  cause  of  muscular  ruptures  when  they  are  per- 
formed with  great  energy  or  speed. 

Sometimes  an  awkward  contraction  tends  to  shorten  a 
muscle  just  when  a  mechanical  cause  is  tending  to 
stretch  its  fibres.  The  muscle,  subject  to  two  opposing 
influences,  is  torn.  We  owe  to  our  friend  Dr.  J.  Lemaistre 
the  observation  of  a  man  who,  in  the  gymnasium,  broke 
a  great  part  of  his  pectoral  muscle.  He  was  a  young 
soldier  performing  a  circle  on  the  rings,  under  the  dread 
of  the  brutal  menaces  of  his  drill-sergeant.  Impelled  by 
the  fear  of  being  punished  if  his  attempt  were  not  bold 
enough,  and  restrained  by  the  fear  of  a  movement  which 
was  new  to  him,  the  gymnast,  after  violently  launching 
his  body  so  as  to  make  a  revolution  from  before  back- 
wards, endeavoured  to  check  himself,  at  a  moment  when 
his  body  was  moving  with  great  speed.  His  body  was 
at  this  moment  as  far  as  possible  from  his  arms,  these 
being  above  his  head.  In  this  position  of  forced  adduc- 
tion, the  fibres  of  the  pectoral — an  adductor  muscle^- 
w^ere  as  much  stretched  as  possible.  Then  an  effort  at 
contraction,  increasing  the  already  excessive  tension,  pro- 
duced their  rupture.  The  inferior  two  thirds  of  the 
muscle  were  torn  through  their  whole  thickness. 

These  effects  of  exercise,  whatever  interest  they  may 
have  for  the  surgeon,  need  not  occupy  us  further,  for 
their  mechanism  is  sufficiently  obvious,  and  their  pro- 
duction is  quite  accidental.  We  shall  pass  on  at  once 
to  other  phenomena  intimately  connected  with  the  phy- 
siological process  of  muscular  contraction,  and  w^hich  are 
the  inevitable  results  of  work. 

III. 

Among  the  most  striking  effects  of  muscular  exercise, 
are  the  changes  undergone  by  the  muscles  themselves 
under  the  influence  of  work.     The   muscles  increase  in 


310  PHYSIOLOGY    OF    BODILY    EXERCISE. 

size,  and  their  structure  is  at  the  same  time  changed  ; 
they  lose  the  fat  which  infiltrates  their  fibres,  and  tend 
to  be  reduced  to  their  own  proper  elements,  the  muscular 
fibres,  the  density 'Of  which,  being  greater  than  that  of 
other  tissues,  gives  a  characteristic  firmness  to  the  region 
which  works.  Further,  the  surrounding  fat  is  burned  up, 
as  well  as  that  which  formed  a  constituent  part  of  the 
organ.  The  cellular  tissue  in  the  midst  of  which  the 
muscles  were  imbedded,  is  burned  to  feed  the  combus- 
tions, and  the  whole  region  undergoes  a  change  of  form 
characterised  by  the  appearance  of  prominences  and 
hollows  ;  the  muscles  stand  out.  We  may  thus,  merely 
by  inspecting  a  man  given  to  violent  exercise  or  laborious 
toil,  determiine  what  parts  of  his  body  are  chiefly  con- 
cerned in  the  muscular  work. 

The  increase  in  size  of  the  muscles  under  the  influence 
of  work  is  due  to  the  greater  activity  of  the  circulation 
during  contraction.  When  a  limb  works,  the  blood  flows 
to  it,  drawn  by  a  physiological  force  which  is  difficult  to 
explain,  but  the  effects  of  which  are  felt  in  all  organs 
which  work,  and  during  the  performance  of  all  functions. 
The  process  in  virtue  of  which  there  is  an  increased 
supply  of  blood  to  a  muscle  during  work,  has  for  its 
object  to  provide  this  organ  with  the  materials  necessary 
for  combustion.  Muscle  in  fact  cannot  produce  work 
without  producing  heat  ;  but  when  it  does  this,  it  is  at 
the  expense  of  certain  substances  brought  to  it  by  the 
blood,  and  it  only  burns  up  its  own  materials  when  the 
supply  from  without  is  deficient.  So  we  only  see  a 
muscle  diffiinished  in  size  by  work  in  cases  of  organic 
exhaustion,  when  the  impoverished  constitution  cannot 
supply  blood  rich  enough  in  combustible  materials. 

Thanks  to  the  unceasing  supply  of  materials  from  the 
blood,  the  muscle  does  not  use  up  its  own  substance 
unless  the  contraction  be  exaggerated  or  unduly  pro- 
longed. In  cases  of  persistent  overwork  the  muscles  end 
by  losing  in  size  and  feeding  on  themselves,  as  we  see  in 
certain  professional  runners  whose  legs  are  extremely 
small,  owing  to  the  manner  in  which  they  have  been 
abused.     The  muscle  which   performs  excessive  work 


LOCAL    EFFECTS    OF    EXERCISE.  31I 

consumes  itself  in  the  end,  the  materials  supplied  by  the 
blood  are  no  longer  sufficient  to  feed  the  combustions. 
Similarly  a  furnace  consumes  at  first  the  wood  which  is 
i>upf)lied  to  it,  but  in  the  end,  if  the  heat  be  too  great,  burns 
itself  and  oxidises  the  iron  bars  by  which  it  is  confined. 

Muscle  uses  for  its  combustions  the  materials  placed 
at  its  disposal,  and  it  is  for  this  reason  that  the  surround- 
ing fat  is  the  first  to  disappear,  and  the  right  arm,  for 
example,  working  alone,  may  lose  its  fatty  tissue,  and 
present,  through  the  thin  skin  very  pronounced  muscular 
prominences,  while  the  left  arm  which  has  remained  in- 
active, still  preserves  a  rounded  and  plump  form  due  to 
the  infiltration  of  the  subcutaneous  cellular  tissue  with 
exuberant  fatty  materials. 

Thus  work,  besides  producing  general  effects  on  nutri- 
tion, begins  by  changing  the  local  structure  of  the  region 
which  is  chiefly  at  work.  Hence  it  is  important,  from  an 
aesthetic  point  of  view,  to  demand  an  equal  amount  of 
work  from  all  the  regions  of  the  body,  if  we  wish  to 
avoid  remarkable  irregularities  of  external  conformation. 

The  increase  in  size  of  a  muscle  is  easily  explained. 
Contraction  draws  to  it  a  greater  quantity  of  blood,  and 
the  increased  flow  continues  even  when  the  work  is  over. 
This  more  considerable  afflux  of  blood  causes  more 
active  nutrition  through  the  abundance  of  materials  in 
which  the  muscular  fibres  are  bathed,  and  which  place  at 
its  disposal  more  nutritive  elements. 

But  increase  in  size  is  not  the  only  change  observed  in 
a  muscle  as  a  result  of  work  ;  we  may  notice  also  a  change 
of  shape  corresponding  to  the  movement  it  performs. 

This  is  one  of  the  most  interesting  of  the  local  effects 
of  work,  for  it  is  intimately  connected  with  the  mechan- 
ism of  the  deformities  which  certain  exercise  may 
produce.  A  muscle  which  is  more  constantly  in  action 
than  other  muscles,  or  in  other  words,  a  muscle  whicli 
contracts  more  often  than  its  antagonist,  undergoes  in 
the  end  a  certain  degree  of  shortening.  If,  for  example, 
the  two  extremities  of  a  flexor  muscle  are  very  often 
approximated    by   contraction,   and    its   action   is   not 


312  PHYSIOLOGY    OF    BODILY    EXERCISE. 

counterbalanced  by  an  equally  frequent  and  energetic 
contraction  of  the  extensor  which  opposes  it,  its  fibres 
tend  to  preserve  the  form  which  they  so  often  assume, 
and  the  muscle  becomes  shorter. 

We  often  observe,  in  gymnasts,  this  partial  contraction 
of  the  muscles,  and  consequently  the  predominance  of 
a  particular  attitude.  Those  who  abuse  the  exercises 
needing  the  flexion  of  the  fore-arm  on  the  arm  acquire  an 
excessive  development  of  the  biceps,  and  this  muscle 
tends  to  becomes  shorter  as  it  becomes  thicker  ;  the 
movement  of  extension  thus  becomes  limited,  and  the 
fore-arm  cannot  be  placed  in  the  same  straight  line  as 
the  arm.  Hence  arises  a  deformity  which  is  unim- 
portant in  the  example  given,  but  of  a  kind  which  may 
become  serious  if  it  involves  certain  regions  of  the  body, 
the  direction  of  which  must  be  regular  under  pain  of 
defect  in  harmony  of  contour  and  in  elegance  of  position. 

Let  us  suppose  that  this  muscular  contracture  which 
is  so  frequent  in  the  arms  of  men  who  practise  much  on 
the  trapeze,  occurs  in  the  muscles  of  the  dorsal  region  : 
the  same  vicious  effects  which  we  have  just  described  in 
the  direction  of  the  arms,  now  influence  the  direction  of 
the  vertebral  column.  If  the  flexor  muscles  of  the  ver- 
tebrae act  more  than  the  extensors,  they  tend  to  shorten, 
while  their  antagonists  preserve  their  normal  size,  and 
the  spine  is  curved  forwards.  Hence  an  unavoidable 
stoop.  If  the  lateral  muscles  of  the  spine  have  received 
the  preference  in  exercise,  it  is  in  them  that  we  observe 
shortening  of  the  fibres.  The  spine  will  be  drawn  to 
the  right  cr  to  the  left  according  as  the  muscles  of  one 
side  have  become  more  developed  than  those  of  the 
other.  There  thus  occur  lateral  deviations,  or,  to  use  the 
technical  term,  scolioses. 

We  shall  see,  in  speaking  of  the  exercises  which  pro- 
duce deformity,  how  frequent  are  scolioses  in  exercises 
which  are  confined  to  one  side  of  the  body,  fencing,  for 
example. 

These  scolioses  are  at  first  purely  muscular,  and  can 
be  rectified,  either  by  giving  up  the  exercise  which  has 
immoderately  developed  the  muscles  of  one  side,  or  by 


LOCAL    EFFECTS    OF    EXERCISE.  313 

practising  an  exercise  which  will  develop  the  muscles  of 
the  opposite  side  after  a  manner  which  will  equalise  the 
action  of  the  antagonists,  and  obtain  an  equilibrium  of 
opposing  forces  which  will  produce  a  straight  spine. 

But  these  means  will  be  insufficient  if  applied  too 
late,  for  it  may  happen  that  the  predominance  of  the 
muscles  of  one  side,  and  the  deviations  which  result 
from  it,  lead  to  consecutive  disturbances  in  the  nutrition 
of  the  vertebrae,  and  to  malformation  of  these  bones. 

In  fact,  the  vertebral  column  is  constructed  of  a 
number  of  very  short  bones,  piled  one  on  top  of  the 
other,  and  each  capable  of  moving  upon  the  one  which 
supports  it.  If  a  vertebra  is  drawn  to  the  right,  for 
instance,  the  movement  which  it  performs  throws  its 
weight  on  to  its  right  edge  and  tends  to  raise  its  left 
half.  All  the  pressure  which  it  exercises  on  the  bone 
which  supports  it,  is  then  localised  to  the  right  ;  but  this 
pressure  which  is  now  borne  by  a  very  limited  part  of 
the  vertebra,  represents  a  considerable  weight,  that  in 
fact  of  the  whole  body  above  the  particular  vertebra. 
This  pressure  hinders  the  process  of  nutrition  of  the 
bone,  which  tends  to  atrophy  at  the  part  pressed  upon. 
On  the  contrary,  the  left  part  of  the  vertebrae  undergoes 
no  arrest  of  development,  for  it  receives  less  weight 
than  in  the  normal  condition  :  it  keeps  its  ordinary  size, 
and  the  bone  definitely  assumes  an  angular  shape  ;  its 
left  half,  which  has  undergone  no  abnormal  pressure, 
remains  thick,  while  the  right  half,  which  has  been 
pressed  upon,  has  become  thin.  Its  shape  exactly  re- 
sembles that  of  the  keystone  of  an  arch,  and  this  shape 
is  repeated  in  all  the  vertebrae  which  undergo  the  same 
deforming  influences.  Hence  a  curvature  of  the  whole 
dorsal  spine,  with  its  concavity  to  the  right  ;  a  curvature 
difficult  to  remedy,  for  it  is  no  longer  due  to  simple  mus- 
cular action,  but  to  material  deformity  of  bones. 

Deformities  of  the  spine  are  the  dangers  of  gym- 
nastics. As  useful  as  are  bodily  exercises  in  remedying 
deviation  of  the  figure  when  they  are  employed  with 
discernment,  they  are  equally  capable  of  producing  them 
when  unmethodically  applied. 


CHAPTER  IV. 

EXERCISES   WHICH   PRODUCE   DEFORMITY. 

Gymnastics  and  i^sthetics — A  rooted  prejudice  ;  the  Beauty 
of  Form  of  Gymnasts-Deformities  due  to  Gymnastics  wiih 
Apparatus — Mechanism  of  these— Too  much  Exercise  of  the 
Arms — Attitudes  of  Support — Breasting — The  Horizontal  Bar — 
The  Parallel  Bars — Circling — The  Trapeze — The  Round  Back 
of  Gymnasts — Fencmg — "  Fencers'  Scoliosis  " — Comparative 
Observations  on  Right- Handed  and  Left- Handed  Fencers — Our 
conclusions  are  opposed  to  those  of  former  authors — Opin  on 
of  Bouvier  and  Boulland — Mechanism  of  these  Deformities — 
Different  attitudes  of  the  Fencer  during  the  different  Stages  of 
a  Fencing-Bout — Guard,  Attack,  Parry,  and  Thrust — Dumb- 
Bells — Riding — Different  Effects  of  Riding  in  a  Race,  and  of  the 
riding  of  the  Schools — The  Back  of  a  Jockey,  and  the  Figure  of 
a  Cavalry  Officer. 

I. 

When  we  attend  a  gymnastic  display,-  and  study  at 
leisure  the  conformation  of  the  young  people  who  take 
part  in  it,  we  have  a  certain  feeling  of  disappointment — 
What  !  is  this  then  the  harmony  of  form,  the  pureness 
of  contour,  which  our  gymnasts  should  find,  like  the 
old  Greeks,  in  the  practice  of  physical  exercise  ? — 
Examine  the  antique  statues  of  "  Achilles,"  of  the 
"  Fighting  Gladiator,"  and  of  the  "  Discobolus,"  and  you 
cannot  help  saying  that  if  these  heroes  v/ere  moulded  by 
gymnastics,  they  m.ust  have  been  gymnastics  quite  unlike 
ours.  Let  us  admit  that  no  one  has  less  the  appearance 
of  a  demi-god  than  a  performer  on  the  trapeze. 

It  is  difficult  to  resist  the  tide  of  formed  opinion, 
which,  for  half  a  century,  has  represented  the  gymnasts 
as  types  of  beauty,  and  we  admire  them  on  trust  with 
our  eyes  shut.  Let  us  then  open  our  eyes  and  study  a 
man  who  has  assiduously  practised  on  the  rings,  the 
horizontal  bar,  and  other  gymnastic  apparatus. 


EXERCISES    WHICH    PRODUCE    DEFORMITY.      315 

The  most  striking  things  about  a  professional  gym- 
nast are  the  exaggerated  development  of  the  bust,  and 
the  small  size  of  the  lower  half  of  the  body.  The 
shoulders  are  very  broad,  the  hips  narrow,  the  legs 
slender.  The  part  of  the  bod>-  whose  office  it  is  to 
support  should  naturally  be  very  muscular,  and  it  is  a 
first  anomaly  to  see  that,  on  the  contrary,  the  upper 
half  of  the  body  exceeds  the  lower  in  size  and  vigour. 

This  anomaly  is  easily  explained  if  we  call  to  mind  the 
mechanism  of  these  exercises.  They  all  need  a  veritable 
transposition  of  the  action  of  the  limbs,  and  make  the  arms 
play  the  part  of  the  legs.  They  all  need  the  support  of 
the'bod}^  b}-  the  shoulders,  whether  the  arms  suspend  \\\ç^ 
body  be'low  the  bar  of  the  trapeze,  or  support  it  above  the 
same.  The  shoulders  must  then  in  these  exercises  gain  a 
development  fitting  them  to  do  the  work  of  the  hips. 

Besides  the  defective  proportion  we  have  pointed  out, 
the  professional  gymnast  shows  a  very  characteristic 
deformity  :  he  has  a  round  back. 

If  we  look  sidewa}-s  at  a  man  who  for  some  years  has 
assiduously  exercised  on  the  trapeze  and  the  parallel  and 
horizontal'bars,  we  see  that  the  line  of  the  back  from 
the  neck  to  the  loins  has  a  ver}'  pronounced  convexity. 
This  is  an  exaggeration  of  the  natural  dorsal  curvature, 
and  sometimes  attains  the  dimensions  of  a  true  deformity 
in  persons  who  practise  exclusively  such  exercises  as 
those  above  micntioned. 

This  is  not  all.  The  shoulders  are  also  the  seat  of  a  cha- 
racteristic deformity.  The  scapula,  drawn  forwards  by  its 
articular  head,  undergoes  at  the  same  tim.e  a  movement  of 
rotation  which  causes  the  inferior  angle  to  rise  and  to  pio- 
ject  backwards.  This  makes  a  protuberance  in  the  back 
comparable  to  that  which,  in  extremely  emaciated  phthi- 
sical patients,  produces  the  alar  chest,  with  this  difference 
that,  in  g}'minasts,  the  bony  prominences  are  accompanied 
by  great  muscular  prominences,  while  in  cachectic  persons 
the  angleof  the  bone  seems  ready  to  break  through  the  skin. 
In  front,  the  line  which  forms  the  profile  of  the  chest 
is  flat,  and  even  re-entrant.  A  pronounced  prominence 
exists  in  the  region  of  the   nipple,  but   it  is   due  to  an 


3l6  PHYSIOLOGY    OF    BODILY    EXEPXISE. 

exaggerated  development  of  the  pectoral  muscles  rather 
than  to  arching  of  the  ribs.  The  thorax  is,  however,  in- 
creased in  size  in  gymnasts,  but  chiefly,  as  we  shall  see, 
in  those  who  exercise  their  legs.  In  gymnasts  who  use 
their  arms  chiefly,  the  apparent  size  of  the  chest  is  largely 
d,ue  to  the  development  of  the  muscles  of  the  shoulder, 
back,  and  chest.  The  antero-posterior  diameter  of  the 
thorax  is  certainly  not  diminished  in  these  persons,  it  is 
even  increased,  but  the  increase  takes  place  behind  only, 
through  the  roundness  of  the  back.  The  chest  is  not 
really  re-entrant,  but  it  looks  so,  owing  to  the  forward 
tendency  of  the  shoulders. 

Such  are  the  deformities  observed  usually  in  our  gym- 
nasts— not  in  all,  but  in  those  who  practise  orthodox 
gymnastics  to  excess  :  we  may  say  the  old  style  of  gym- 
nastics, for  there  is  happily  a  reactionary  tendency 
against  it.  This  deformity  is  due  to  abuse  of  the 
exercises  demanding  suspension  and  support  of  the  body 
by  the  hands.  Now  these  are  the  two  fundamental  posi- 
tions of  gymnastics  performed  with  the  aid  of  apparatus. 

When  the  body  is  moved  in  order  to  pass  from  sus- 
pension to  support  by  the  arms,  this  change  is  effected 
by  two  methods,  breasting  mid  circling. 

In  the  breasting  movement,  the  body  is  first  suspended 
by  the  fully  extended  arms  to  two  rings  or  to  a  hori- 
zontal bar,  then  it  is  drawn  up  by  a  contraction  of  the 
biceps,  which  brings  the  shoulders  to  the  level  of  the 
wrists.  At  this  moment  the  difficulty  begins.  It  is 
necessary  that  the  elbows,  which  are  lower  than  the 
hands,  should  be  raised  above  them,  in  such  a  manner 
that  the  body,  instead  of  being  suspended,  comes  to  be 
supported  by  the  arms. 

To  pass  from  suspension  to  support,  the  gymnast  must 
raise  himself  above  a  bar  of  wood  if  he  is  on  a  trapeze,  or 
above  an  imaginary  line  if  he  is  on  the  rings.  In  both  cases 
the  centre  of  gravity  of  his  body  must  pass  behind  this 
line  in  order  eventually  to  attain  a  position  above  it. 

If  w^e  observe  the  different  movements,  we  see  the 
muscles  of  the  back  of  the  neck  contract  energetically 


EXERCISES    WHICH    PRODUCE    DEFORMITY.      317 

with  an  effort  which  seems  to  thrust  the  neck  down  be- 
tween the  shoulders.  The  whole  body  is  drawn  together, 
and  the  dorsal  region  of  the  spine  strongly  curved  in 
order  to  bring  the  shoulders  as  far  as  possible  in  front 
of  the  bar  and  thus  lighten  the  work  of  the  arms,  at  the 
same  time  as  the  pelvis  is  raised  as  much  as  possible,  to 
lift  the  whole  weight  of  the  body  and  raise  the  centre  of 
gravity.  The  gymnast  has  at  this  moment  the  most  un- 
graceful appearance  it  is  possible  to  imagine.  Now  we 
know  that  the  body  tends  to  preserve  the  imiprint  of  an 
often  repeated  attitude. 

This  drawn  attitude  of  the  upper  part  of  the  body,' 
with  exaggerated  flexion  of  the  upper  six  or  eight  dorsal 
vertebrae,  is  characteristic  of  all  the  breasting  movements. 

It  also  occurs  in  the  circling  movement,  which  needs 
the*  revolution  of  the  body  round  the  bar  of  a  trapeze,  or 
round  the  imaginary  line  between  the  rings.  All  these 
exercises  need  a  forced  flexion  of  the  dorsal  part  of  the 
spine,  and  tend  to  produce  a  round  back. 

Other  gymnastic  exercises  seem,  at  first  sight,  calculated 
to  counterbalance  the  effect  of  those  the  disadvantages  of 
which  we  have  j  ust  described.  If  the  trapeze  and  the  hori- 
zontal bar  bring  into  action  the  flexors  of  the  spine,  we  may 
say  that  on  the  parallel  bars,  on  the  contrary,  the  exten- 
sors are  especially  employed.  This  is  true  enough,  and 
yet  these  exercises  have  no  tendency  to  correct  the  arched 
appearance  of  the  back  produced  by  the  trapeze. 

In  fact,  the  parallel  bars,  like  all  the  apparatus  which 
reed  the  support  of  the  body  on  the  hands,  tend  to 
throw  the  shoulders  forwards,  in  such  a  manner  that, 
without  increasing  the  curvature  of  the  spine,  they  render 
it  more  apparent.  When  the  body  is  supported  by  the 
arms,  which  transmit  the  weight  to  the  shoulders,  it  is 
necessary  that  the  numerous  muscles  surrounding  the 
scapula,  the  clavicle,  and  the  head  of  the  humerus,  should 
contract  energetically,  in  order  to  make  of  these  bones  a 
solid  and  résistent  whole,  capable  of  assuming  the  oflice 
of  the  pelvis.  The  muscles,  on  which  falls  the  major 
part  of  this  work  of  consolidation  of  an  essentially  mobile 
•     ■      22 


3l8  PHYSIOLOGY    OF    BODILY    EXERCISE. 

region,  are  the  pectorals,  for  their  action  is  to  draw  the 
shouldQV s  forwards  and  inwards,  and  this  is  the  position 
always  assumed  by  the  head  of  the  humerus  in  exercises 
on  the  parallel  bars. 

In  a  man  rtioving  along  the  parallel  bars  supported  by 
his  extended  arms,  the  trunk  hanging  down  by  its  own 
weight,  it  is  easy  to  see  that  a  line  traversing  the  shouldei  3 
is  much  in  advance  of  one  passing  through  the  same  points 
in  a  man  standing  upright  at  attention.  It  is  the  energetic 
and  sustained  contraction  of  the  pectorals  which,  during 
the  whole  period  of  support  on  the  arms,  gives  to  the 
articular  head  of  the  scapula  this  forward  direction.  Fur- 
ther, the  distance  between  the  bars  being  always  greater 
than  the  width  of  the  shoulders,  the  arms  are  thrust  at  once 
from  below  upwards,  and  from  witJwut  inwards  by  the 
force  they  transmit  to  the  scapulo-humeral  articulation. 

In  other  words,  the  parallel  bars  have  a  tendency,  to 
thrust  the  shoulders  inwards,  to  raise  them,  and  to  carry 
them  forwards. 

We  need  not  here  insist  on  the  physiological  mechanism 
which  tends  to  render  an  often  repeated  attitude  perma- 
nent. We  will  merely  recall  that  a  muscle  which  contracts 
often  and  energetically,  tends  definitely  to  shorten,  and  con- 
sequently to  draw  its  origin  and  insertion  nearer  together. 
Thus  it  is  that  after  sustained  and  repeated  exercise  the 
pectoral  muscle  tends  to  draw  its  more  movable  point  of  at- 
tachment, which  is  the  neck  of  the  humerus,  nearer  to  its  more 
fixed  point  of  attachment,  which  is  the  front  of  the  chest,  or 
in  other  words,to  draw  the  shoulders  forwards  and  inwards. 

Finally,  the  thrust  of  the  humerus  from  below  upwards, 
tends  to  leave  its  imprint  on  the  conformation  of  the 
gymnast,  either  by  the  deformity  it  produces  in  the 
clavicle  itself,  exaggerating  the  curves  of  this  bone,  and 
consequently  shortening  it,  or  in  the  articular  cavities  by 
changing  their  depth  and  direction. 

The  analysis  of  the  movements  explains  then  what  a 
glance  is  sufficient  to  determine  ;  that  gymnastic  exercises 
performed  with  the  aid  of  apparatus  deform  those  who 
abuse  them. 


EXERCISES    WHICH    PRODUCE    DEFORMITY.      319 

They  tend  to  draw  the  body  together  and  give  it  a 
curved  appearance  :  (i)  by  developing  to  an  exaggerated 
degree  the  muscles  of  the  shoulders  and  back  ;  (2)  by 
exaggerating  the  dorsal  curvature  of  the  spine  in  the 
upper  half  of  its  extent. 

They  have  no  tendency  to  diminish  the  actual  size  of 
the  thorax,  but  they  make  the  chest  appear  sunken  by 
carrying  the  shoulders  forwards,  inwards,  and  upwards. 

This  simple  exposition  will  doubtless  have  more  value 
than  a  long  pleading  to  make  it  clear  that  the  trapeze 
will  not  be  a  regenerator  of  beauty  of  form.  And  yet 
for  a  long  time  to  come  people  will  religiously  bow  down 
before  the  anti-physiological  traditions  oï  gymnastics  with 
apparatus  which  we  owe  to  Colonel  Amoros. 

11. 

Gymnastic  exercises  are  not  the  only  ones  which 
produce  deformity.  Another  athletic  exercise  which  is 
much  practised  now-a-days,  fencing,  produces  also  very 
characteristic,  although  less  pronounced  deformities. 

We  have  collected  on  this  subject  a  series  of  obsen^a- 
tions  which  were  presented  in  January  1886  to  the 
Medical  Society  at  Limoges,  and  the  conclusions  from 
which  are  diametrically  opposed  to  those  which  had 
hitherto  been  obtained  in  the  matter.  We  shall  here 
describe  the  phenomena  we  ourselves  observed,  and  the 
physiological  interpretation  we  have  given  of  them. 

Everyone  who  has  fenced  much  shows  in  a  more  or 
less  pronounced  degree  a  lateral  curvature  of  the  spine. 
As  to  the  direction  of  this  curvature,  this  scoliosis^  we 
may  say  that  all  right-handed  fencers  tend  to  have 
scoliosis  with  the  concavity  to  the  right,  and  all  left- 
handed  ones  scoliosis  with  the  concavity  to  the  left. 
T  hese  tendencies  are  very  unequally  marked.  Hardly 
indicated  in  some  cases,  they  may  become  serious 
deformities  in  others.  W^e  need  hardly  point  out  that 
the  vertebral  column  of  an  adult,  solidly  built,  in  a 
vigorous  man  who  fences  at  long  intervals,  could 
perfectly   resist    the    tendency,    and    take    no    vicious 


320  PHYSIOLOGY    OF    BODILY    EXERCISE. 

direction,  while  the  maximum  deformity  would  be 
produced  in  a  subject,  liable  to  rickets  or  softening-  of 
the  bones,  who  had  begun  to  fence  when  quite  a  child, 
and  continued  assiduously  till  grown  up.  Between  these 
two  extremes  there  are  many  degrees,  but  we  must  say 
that,  generally,  a  methodical  examination  is  necessary  to 
establish  the  existence  of  deformity. 

The  deformity,  even  when  very  pronounced,  is  usually 
imperceptible  at  the  first  glance.  The  practice  of  fencing 
develops  in  fact,  more  than  any  other  exercise,  agility 
and  precision  of  movement  ;  it  gives  a  certain  ease  and 
grace  in  the  carriage  which  compensate  for,  and  mask 
after  a  fashion,  the  slight  deviation  of  the  trunk. 

On  close  examination, however, of  those  who  frequent  the 
fencing  school,  we  find  the  characteristic  signs  of  scoliosis. 
Among  these  there  is  one  for  which  surgeons  usually  look 
first,  because  it  is  the  most  striking  :  this  is  the  deviation  of 
the  line  formed  by  the  spinous  processes  of  the  dorsal  ver- 
tebras. This  sign  is  not  often  present  in  scoliosis  due  to 
fencing,  for  in  these  cases  the  deformity  is  usually  slight, 
and  the  sign  of  which  we  speak  is  only  met  with  where  the 
curvature  is  very  pronounced.  We  have  observed  it,  how- 
ever, in  a  youth  of  sixteen  years  of  a  feeble  constitution, 
who  fenced  to  excess,  and  who  had  strengthened  his 
system  at  the  expense  of  the  straightness  of  his  spine. 

There  are  other  signs  of  deviation  which  we  meet 
much  more  often  in  fencers.  One  of  the  commonest  is 
lowering  of  the  shoulder.  Here  our  observations  are 
absolutely  contradictory  to  the  opinion  of  other  authors. 

In  a  work  by  Bouvier  and  Boulland  *  we  read 
"  Fencing  may  help  to  remedy  a  commencing  scoliosis, 
by  raising  the  shoulder  on  the  side  zvJiich  holds  the  foil!' 
This  sentence  contains  a  great  error,  the  practical  con- 
sequences of  which  may  be  serious.  The  shoulder  of 
the  arm  which  holds  the  foil  in  fencing  is  not  raised  ; 
on  the  contrary,  it  is  lozvcred.  Considering  the  weight  of 
the  authority  we  have  quoted,  we  must  support  our 
contrary  opinion  both  by  observation  of  facts  and  by  a 
rational  study  of  the  different  movements  of  fencing. 

•  Dictionnaire  de  médecine  et  de  chirurgie  pratique,  art.  "  Rachis." 


EXERCISES    WHICH    PRODUCE    DEFORMITY.      32 1 

As  to  facts  our  observations  concerned  twenty  experi-  ■ 
enfed  fencers  among  whom  .vere  eight  fencmg  rnas^ers 
and  three  left-handed  men.  We  wish  first  to  state  that 
the  observations  made  on  the  left-handed  men  gave 
absolutely  inverse  results  to  tl.ose  on  the  "Sht-handed 
and  this  is  a  sufficiently  conclusive  ^«""'^/'P  °°f:,  Z^'^^" 
the  cases  observed,  the  shoulder  has  so  fiequently  been 
owe?^«  //..  s^de  of  the  ^vorking  arm,  that  th.s  deform,  y 
has  become  for  us  the  professional  stamp  of  the  lencing 

""to 'measure  properly  the  degree  f  dife-«.ce  in 
h»i<^ht  it  is  enough  to  put  the  subject  of  examinât  on 
upright  against  a  wall,  and  to  lower  successively  to  he 
7gh?  and  to  the  left  a  T-square  held  edgewise  until  it 
touches  the  prominence  of  the  shoulder  produced  by  the 
a^rmTion  On  each  side  we  rule  here-  a  horizontal  line 
and  we  can  then  measure  the  difference  m  level  between 
?he  tw'o  We  need  hardly  point  out  that  it  is  necessar>^ 
before   measuring    to   -^tain   that   the  ^^ps   01    the 

S^ntTeigM  o^thf  sltld:::  is  ':? due  to  inequality 
Tthe  length  of  the  legs.  By  this  method  we  have 
ound  the  Shoulders  lowered  by  as  much  as  two  and  a 
ha"f  centimetres  in  persons  who  are  vigorous  and  m 
other  respects  well  built. 

Often  the  deformity  is  seen  at  a  glance  We Ja^e 
seen  fencers  whose  linen  vest  showed  a  great  transverse 
fold  over  the  right  pectoral  muscle,  while  it  was  smooth 
S  d  Wretched  over^the  left  side  of  the  chest;,  a  proo 
that  the  right  side  of  the  trunk  was  shortei  than  the 
left  the  shoulder  being  lowered  and  nearer  to  the  hip. 

Finally  there  is  another  sign  of  dorsal  scoliosis  which 
vve  have^arely  found  wanting:  this  is  a  fettemng  of 
one  side  of  the  chest  corresponding  to  a  vaulnng  of  tne 
o"hei  side.  In  right-handed  fencers,  the  flattening  is  at 
?heri-lt  external  part  of  the  thorax,  and  the  vaul  ing 
external  and  to  the  left  ;  in  left-handed  men  the  other 
way  about.  The  vaulting  is  due  to  a  great  P^™"-  ce 
of  the  rib  curves  which  are  pushed  outwaid.  by  the 
convexity  of  this  side  of  the  spine  ;  it  is  usually  accom- 


322  PHYSIOLOGY    OF    BODILY    EXERCISE. 

panied  by  enlargement  of  the  intercostal  spaces.  On 
the  side  of  the  depression,  on  the  contrary,  the  ribs  have 
retreated  or  fallen  in,  being  drawn  inwards  by  the 
vertebral  column  to  which  they  are  attached,  and  which 
on  this  side  is  concave.  The  ribs  which  are  depressed 
are  also  approximated,  and  thus  the  intercostal  spaces 
are  narrowed.  In  very  pronounced  cases,  there  is  not 
merely  a  flattening,  but  an  actual  hollow  on  the  side  of 
the  sword-arm.  In  slight  cases  the  difference  is  still 
sufficiently  noticeable  for  ~  it  to  be  necessary  to  pad  the 
right  side  of  a  fencer's  coat.  Many  tailors  are  well  aware 
of  this  detail,  which  has  its  own  value. 

It  would  be  possible  to  turn  to  the  advantage  of  the 
fencer,  this  tendency  to  deformity  of  the  thoracic  pa- 
rietes  in  c^ses  in  which  there  is  from  other  causes  an 
opposite  deformity.  One  of  the  best  fencers  in  the 
barracks  at  Limoges,  a  left-handed  fencing  master, 
suffered  some  years  ago  from  a  right  pleurisy.  After 
this  illness  the  right  side  of  his  chest  was  depressed,  the 
pleurisy  having  caused,  as  usual,  retraction  of  the  thoracic 
parietes.  Since  then,  fencing  always  with  his  left  hand,  he 
has  unconsciously  remedied  the  right-sided  deformity,  for 
now,  instead  of  a  hollow  here,  there  is  a  slight  convexity. 

Thus  fencing,  always  practised  with  the  same  hand, 
tends  to  produce  a  deviation  of  the  dorsal  spine,  the 
concavity  of  which  corresponds  to  the  hand  which  holds 
the  foil.  This  is  a  lateral  curvature,  a  scoliosis.  It  can 
present  various  degrees,  and  is  more  pronounced  in 
proportion  to  the  slighter  power  of  resistance  of  the 
subject,  to  his  youth,  and  to  the  amount  he  has  fenced. 
This  scoliosis  gives  the  usual  signs  of  lateral  curvature, 
amongst  which  three  are  easy  to  detect.  One  of  these 
only  occurs  in  pronounced  cases  :  this  is  the  deviation 
from  the  vertical  of  the  line  formed  by  the  spinous  pro- 
cesses. The  other  two  are  nearly  constant  and  give  a 
stamp  to  all  men  who  fence  much.  They  are  :  the  lower- 
ing of  the  shoulder  on  the  side  of  the  sword-arm,  with 
flattening  of  the  chest  on  the  same  side,  and  vaulting  on 
the  opposite. 

Such  are  the  results  of  observation  ;  let  us  now  seek 


EXERCISES    WHICH    PRODUCE    DEFORMITY.      323 

to  give  a  rational  explanation   of  them   by  considering 
the  mechanism  of  fencing. 

When  we  analyse  the  movements  of  a  man  fencing,  we 
see  that  they  all  agree  in  imposing  on  the  body  an  atti- 
tude similar  to  the  vicious  curvature  we  have  described 
Now  we  know  that  an  attitude  often  assumed,  a  curva- 
ture which  the  spine  assumes  every  day,  tends  to  become 
permanent.  It  is  thus  that  deviations  of  the  figure  are 
established  by  habitually  vicious  carriage,  or  by  the 
special  attitudes  of  certain  professions. 

A  complete  summary  of  the  different  movements  of 
fencing  is  presented  by  the  mimic  combat  known  as  the 
assault.  All  the  stages  of  the  assault  may  be  reduced  to 
three:  the  guard,  the  attack,  the  parry  ;  the  thrust  needs 
no  special  description,  it  is  merely  an  attack  rapidly 
following  a  parry. 

In  tJie  guard,  the  right-handed  fencer  raises  his  left 
shoulder  to  carry  his  arm  above  his  head  ;  his  right 
shoulder  is  on  the  contrary  lowered,  in  carrying  his  hand 
to  the  level  of  his  right  breast.  His  face  is  turned 
tow^ards  his  opponent,  but  his  body,  to  show  less  front,  is 
turned  sideways.  Thus  when  the  fencer  leans,  his  body 
is  not  bent  forwards,  but  to  the  side,  in  the  direction  of 
his  opponent,  and  consequently  in  the  direction  of  his 
sword-arm.  They  always  lean  over,  academic  principles 
notwithstanding,  and  two  fencing  masters  in  the  assault 
lean  over  quite  as  much  as  their  pupils.  A  man  leans 
more  in  proportion  to  the  attention  with  which  he  is 
watching  his  opponent  to  seize  the  moment  for  attack. 
A  man  then  draws  himself  together  like  an  animal 
crouching  for  a  spring,  and  the  body  bends  more  and 
more  before  being  extended.  It  is  at  this  moment,  in 
this  forced  attitude,  that  the  vertebral  column  is 
most  fatigued  and  has  the  greatest  tendency  to  cur- 
vature. 

In  the  attack,  the  fencer  lunges,  that  is,  the  trunk  is 
carried  forwards  and  violently  bent  towards  the  opponent 
in  the  endeavour  to  reach  him.  The  vertebral  column, 
in  this  lateral  displacement,  may  be  compared  to  the 
arm  of  a  lever,  the  extremity  of  which  is  charged  with 


324  PHYSIOLOGY    OF    BODILY    EXERCISE. 

the  weight  of  the  head  and  shoulders,  a  weight  which 
adds  to  the  shock  of  flexion  in  compressing  the  sides  of 
the  vertebral  bodies  (right  side  in  right-handed,  left  in 
left-handed  men).  This  pressure  often  repeated,  and 
always  on  the  same  points,  comes  in  the  end  to  hinder 
the  nutrition  of  the  vertebrae.  If  these  have  little  power  of 
resistance,  and  if  the  violence  is  often  repeated,  there  results 
a  subsidence,  a  settlement  of  the  bones  on  the  side  which 
is  compressed,  while  the  other  side  keeps  its  normal  size. 
The  whole  column  undergoes  this  process  of  unilateral 
subsidence  and  consequent  deviation  from  the  vertical. 

In  the  parry,  the  body  does  not  move,  the  fore-arm  and 
the  wrist  are  alone  in  action  ;  but  the  fencer  always 
preserves  the  position  of  lateral  flexion  which  we  described 
in  the  guard,  for  it  is  necessary  that  the  body  should  be 
ready  at  any  moment  to  thrust. 

Thus  in  all  the  phases  of  fencing, -the  body  acts  in,  and  is 
fatigued  by,  maintaining  a  position  which  forces  the  trunk 
to  incline  constantly  to  the  side  of  the  sword-arm.  The 
vertebral  column  may  be  compared  to  a  bow  which  is 
stretched  and  loosened,  forming  a  curve,  the  concavity  of 
which  corresponds  to  the  hand  which  does  the  work.  This 
curvature,  being  often  repeated  and  long  continued,  what 
is  there  to  surprise  us,  if  the  body  preserves  its  stamp  ? 

Reasoning  is  then  in  agreement  with  facts  in  leading 
us  to  the  following  conclusions  : — 

If  we  wish  to  employ  fencing  with  a  therapeutic  end 
in  a  feeble  person,  at  an  age  when  deviations  of  the  spine 
are  to  be  feared,  we  must  recommend  that  both  hands 
should  be  equally  exercised,  not  only  in  order  to  avoid 
an  unequal  development  of  the  muscles  of  one  side  of 
the  body  (which  hitherto  has  been  the  chief  considera- 
tion), but  also,  and  chiefly,  in  order  to  avoid  the  pro- 
duction of  deformity.  If  we  employ  fencing  with  an 
orthopaedic  aim,  in  order  to  try  and  remedy  a  scoliosis, 
ive  must  not  confine  the  exercise,  as  is  recommended  in 
the  above  quotation,  to  the  side  on  which  is  the  con- 
vexity of  the  curve  ;  we  must  do  exactly  the  opposite 
of  this.  If  we  have  to  raise  a  drooping  right  shoulder, 
the  foil  must  be  held  in  the  left  hand,  and  conversely. 


EXERCISES    WHICH    TRODUCE    DEFORMITY.      325 

We  are  unwilling  to  conclude  this  study  without 
speaking  of  a  very  common  practice  at  fencing-schools, 
which,  in  the  endeavour  to  remedy  the  evil  effects  of 
fencing,  really  rather  exaggerates  them.  With  the  object 
of  exercising  the  side  of  the  body  which  has  not  been  at 
work,  we  see  a  fencer,  after  a  bout  in  which  he  has  usetl 
his  right  hand,  set  methodically  to  work  with  a  dumb-bell 
in  his  left  hand,  not  considering  the  very  different  effects 
of  these  two  exercises.  Dumb-bells,  in  contra-distinction 
to  fencing,  raise  the  shoulder  of  the  side  which  works. 
In  fact,  by  a  compensatory  movement  which  does  not 
occur  in  fencing,  during  the  whole  time  that  the  left  arm 
is  using  the  dumb-bell,  the  body,  in  order  to  balance 
itself,  leans  towards  the  right,  and  resumes  the  exact 
position  which  the  man  wishes  to  avoid. 

There  is  only  one  way  of  avoiding  the  deviation  which 
occurs  in  a  man  who  fences  w4th  one  hand  only  ;  this  is 
to  use  alternately  the  right  hand  and  the  left. 

Riding  may  be  classed  amongst  the  exercises  which 
produce  deformity,  but  the  deformities  produced  vary 
according  to  different  modes  of  riding. 

In  professional  horsemxn  there  exists  a  curvature  of  the 
lower  limbs,  which  is  more  pronounced  in  proportion  to  the 
greater  malleability  of  the  limbs  at  the  period  when  the  ex- 
ercise began.  The  legs  tend  to  become  concave.  It  is  by 
being  as  it  were  moulded  around  the  horse's  trunk  that 
the  lesfs  and  thig-hs  of  the  horseman  become  arched. 

Another  deformity  may  be  pointed  out  as  occurrmg 
in  persons  who  ride  in  races  ;  this  is  an  arching  of  the 
back.  The  jockey  leans  forward  to  lighten  as  much  as 
possible  the  horse's  hindquarters.  But,  besides  this 
attitude  w^hich  curves  the  dorsal  region  of  the  spine, 
there  is  a  more  active  cause  of  deformit}^.  The  arms  must 
support  the  horse's  mouth,  and  thus  support  a  weight 
often  exceeding  20  kilogrammes.  To  sustain  this  pull 
the  jockey  supports  himself  by  his  stirrups  and  knees.  The 
body  is  thus  under  the  influence  of  two  forces,  which  tend 
to  draw  nearer  together  the  two  extremities  of  the  dorsal 
arch,  and  thus  to  exaggerate  its  curvature. 


326  PHYSIOLOGY    OF    EODILY    EXERCISE. 

The  horsemanship  of  the  riding-school  and  that  of 
ordinary  out-door  riding  seldom  follow  the  same 
methods  as  race  riding,  and  tend  to  give  the  body  a 
perfectly  balanced  and  consequently  a  perfectly  vertical 
position.  The  horseman  must  be  in  a  position  most 
favourable  to  firmness  of  seat,  that  is,  he  must  bend 
neither  forwards  nor  backwards,  neither  to  the  right  nor 
to  the  left,  and  he  is  forbidden  to  gain  any  support  from 
his  reins.  His  vertebral  column  must  always  be  ready 
to  move  in  all  directions  when  necessary  to  maintain 
equilibrium,  and  for  this  the  vertebrae  must  remain  very 
freely  movable  on  each  other.  The  pieces  which  build 
up  the  vertebral  column  must  not  then  undergo  any 
excessive  pressure  ;  drawing  together  of  the  loins  or 
back  must,  above  all,  be  avoided,  under  pain  of  deficient 
flexibility. 

Observation  has  shown  us  the  great  difference  betvv^een 
the  horse  soldier  and  the  jockey  from  the  point  of  view  of 
form.  Old  jockeys  are  drawn  together,  have  high 
shoulders  and  a  round  back.  Cavalry  officers  preserve, 
on  the  contrary,  a  remarkable  elegance  of  figure  even  in 
advanced  age. 

It  ÎS  impossible  for  us  to  analyse  all  the  exercises 
which  produce  deformity.  The  types  we  have  described 
sufficiently  point  out  the  method  to  be  followed  in 
judging  of  the  influence  of  muscular  work  on  the  form  of 
the  body. 

We  may  say  generally  that  an  exercise  will  produce 
more  or  less  marked  bodily  deformity,  whenever  it  is 
performed  under  the  following  conditions  : — 

(i)  Concentration  of  muscular  effort  in  a  very 
localised  region,  the  other  parts  of  the  body  not 
sharing  in  the  work. 

(2)  Necessity  of  maintaining  during  the  exercise  an 
attitude  in  which  the  axis  of  the  body  deviates  from  its 
normal  direction. 

(3)  Frequent  and  prolonged  performance  of  move- 
ments which  man  does  not  naturally  practise,  and  ta 
which  his  conformation  is  not  adapted. 


CHAPTER  V. 

EXERCISES  WHICH  DO   NOT   PRODUCE  DEFORMITY. 

The  best  Gymnastic  Exercises— Ground  Exercises— An  Exercise 
too  little  reç^arded  ;  French  Boxing  or  Chatisson—Y^ix  division 
of  work  in  this  Exercise  :  Necessity  for  Perfect  Equihbriup  ; 
Boldness  of  the  Movements— T/^^  Turning  /iTz^^- Swimming 
and  Climbing— Rowing— Two  Varieties  of  Boating  Exercise  ; 
the  Oar  and  the  Paddle— Superiority  of  the  Oar— Rowmg  and 
Scullino-— General  conditions  of  Exercises  which  do  not  produce 
Deformity  ;  these  conditions  are  especially  Negative— Natural 
tendency  of  the  Body  to  Regular  Development— Exercise  must 
not  oppose  this  tendency— Suppleness  a  condition  of  Elegance 
of  Figure— Superiority  of  Exercises  of  Skill  to  Exercises  of 
Streno-th— Rope-dancers  ;  Jugglers  and  Balancers— The  habit 
of  carrying  Burthens  on  the  Head— The  Women  of  Tenenffe. 

1. 

The  conclusions  we  enunciated  in  the  last  chapter  may 
serve  to  guide  us  in  pointing  out  the  conditions  in  which 
exercise  must  be  practised  in  order  to  maintain  the 
regular  form  of  the  body. 

The  exercises  which  produce  bodily  deformity  are,  m 
the  first  place,  those  which  do  not  make  all  parts  of  the 
body  work  equally.  If  we  are,  before  all  things,  anxious 
to  preserve  regularity  of  form,  we  must  adopt  exercises 
in  which  all  parts  of  the  body  regularly  perform  work 
in  proportion  to  the  strength  of  their  muscles.  ^ 

In  the  gymnasium  we  call  ground  exercises  those 
which  are  performed  in  the  upright  posture,  and  which 
consist  in  successive  movements  of  flexion,  extension, 
etc.,  of  the  legs,  the  arms,  the  trunk,  the  pelvis,  and  the 
neck.  These  are  evidently,  from  an  aesthetic  point  ot 
view,  the  best  of  all  exercises.  Every  limb  does  work 
in  proportion  to  the  strength  of  its  muscles,  for  it  moves 
only    its   own   weight.      Further,   there   is   a   pertectly 


328  PHYSIOLOGY    OF    BODILY    EXERCISE. 

measured  contraction  of  all  antagonistic  muscles,  and  no 
tendency  to  predominant  contraction  of  flexors  rather 
than  extensors,  or  vice  versa,  and  in  consequence  no 
tendency  to  draw  the  bones  into  abnormal  directions. 
Finally,  the  body  being  supported  on  the  legs  during 
these  exercises,  the  vertebral  column  has  no  tendency  to 
assume  a  vicious  attitude  for  the  maintenance  of  an 
abnormal  equilibrium. 

These  exercises  would  then  be  the  best  of  all  if  they 
were  a  little  more  interesting  to  those  who  practise  them. 
But  they  are  very  unattractive,  as  they  suppress  all 
initiative  on  the  part  of  the  pupil,  and  only  need  an 
attentive  and  passive  obedience  to  orders. 

There  is  happily  another  gymnastic  exercise  which 
combines  with  regularity  in  the  expenditure  of  force  a 
peculiar  attraction,  because  it  implies  a  contest  of  skill, 
agility  and  readiness  :  this  is  French  boxing.  This 
exercise  is  learned  in  a  series  of  lessons  of  which  each 
is  performed  alternately  by  the  right  and  the  left  side  of 
the  body.  In  this  manner  the  right  leg  and  the  right 
arm  repeat  exactly,  when  their  turn  comes,  all  the  miove- 
ments  which  have  just  been  performed  by  the  left  arm 
and  the  left  leg. 

French  boxing,  in  which  blows  are  given  with  the  feet 
as  well  as  with  the  fist,  needs  every  momicnt  attitudes  of 
great  boldness. 

When  a  kick  has  to  be  given  as  high  as  the  face,  the 
trunk  must  be  strongly  inclined  to  the  side  to  counter- 
balance the  displacement  of  the  centre  of  gravity,  and 
this  attitude  would  be  vicious  if  it  were  always  in  the 
same  direction.  But  the  right  leg,  which  has  delivered 
a  kick,  has  hardly  returned  to  the  ground  when  the  left 
leg  must  take  its  turn,  and  repeat  the  attack,  either 
directly  forwards,  or  by  the  pirouette  known  as  the 
turning  kick.  With  a  rapidity  which  astonishes  the 
spectator,  the  body  must  change  from  one  leg  to  the 
other  with  a  sufficiently  stable  equilibrium  to  propel 
the  foot  in  a  precise  direction  with  a  force  which  some- 
times exceeds  50  kilogrammetres.  In  order  that  the 
centre  of  gravity  may  be  displaced  with  such  marvellous 


EXERCISES  WHICH  DO  NOT  PRODUCE  DEFORMITY.     329 

ease,  the  vertebral  column,  which  plays  the  part  of  a 
balancing-pole,  must  preserve  an  extreme  mobility.  The 
inter-vertebral  joints  must  allow  of  very  extensive  move- 
ments, which  are  incompatible  either  with  contracture  of 
the  spinal  muscles,  or  with  anchylosis  between  any  of  the 
vertebra,  or,  finall}^  with  any  vicious  direction  of  the 
articular  surfaces.  'And  these  are  the  three  chief  causes 
of  deviations  of  the  figure. 

French  boxing,  or  cliansson,  is,  then,  preferable  to 
fencing  for  the  regular  development  of  the  body  of  a 
young  man,  and  for  preventing  vicious  carriage. 

Swimming,  like  chausson,  needs  a  regular  action  of 
all  the  muscles.  The  body  must  progress  in  this 
exercise  by  a  movement  of  extension  which,  beginning 
in  the  legs,  spreads  to  the  thighs,  the  vertebral  column, 
and  the  arms. 

(7/zV;/(^zV/^  has  a  great  resemblance  to  swimming.  In 
both  these  exercises  progression  is  brought  about  by 
alternate  movements  of  flexion  and  extension  of  the 
body  and  limbs.  Between  these  two  methods  of  pro- 
gression there  seems  to  be  at  first  sight  only  a  difference 
of  direction  ;  in  swimming  it  is  horizontal,  in  climbing 
from  below  upwards.  But  there  is  a  capital  difference  as 
regards  the  mechanism  of  the  work  ;  in  the  swimmer,  the 
arms  and  shoulders  move  in  the  same  horizontal  plane  ; 
in  the  climber,  on  the  contrary,  the  arms  are-  much  in 
advance  of  the  chest,  and  their  movements  of  flexion,  the 
hands  being  fixed,  tend  to  dravv'  the  shoulders  upwards, 
forwards,  and  inwards. 

We  have  had  no  opportunity  of  observing  the  pro- 
fessional climbers  who  spend  their  lives  in  the  State 
forests  in  climbing  large  trees  for  the  purpose  of  remov- 
ing the  branches.  But,  considering  the  nature  of  the 
work  they  perform,  the  conformation  of  their  shoulders 
should  resemble  that  of  the  gymnasts  who  make  too 
much  use  of  the  trapeze.  In  the  exercise  of  swimming 
there  is,  on  the  contrary,  no  cause  of  deformity,  and 
swim.mers  have,  therefore,  generally  a  very  regular 
development. 


330  PHYSIOLOGY    OF    BODILY    EXERCISE. 

There  are  certain  exercises  which  seem  at  first  sight 
to  be  performed  by  a  very  locahsed  group  of  muscles, 
but  which  a  more  attentive  analysis  shows  to  be 
generalised  throughout  the  body.  Thus  a  man  who 
rings  a  heavy  bell  does  not  only  work  with  his  hands 
which  hold  the  rope,  but  with  his  arms  which  bend,  with 
his  trunk  which  leans  forward,  even  with  his  feet,  which 
contract  in  order  to  adhere  more  firmly  to  the  ground. 

Rowing  is  reputed  to  increase  the  size  of  the  biceps, 
and  this  sport  is  generally  classed  with  exercises  of  the 
arms.  This  is  a  mistake,  for  the  work  of  the  rower  is 
far  from  being  localised  in  his  upper  limbs.  The 
muscular  effort  which  moves  on  the  boat  is  largely 
situated  in  the  extensors  of  the  vertebral  column.  The 
oarsman  pulls  above  all  with  his  loins.  Further,  when 
the  boat  is  to  be  propelled  with  great  speed,  as  in  racing, 
the  legs  work  at  least  as  much  as  the  arms. 

As  we  are  writing  these  lines  we  are  suffering  from  an 
attack  of  muscular  stiffness  produced  by  resuming  the 
exercise  of  rowing  after  a  year's  interval.  In  the 
muscles  of  the  arms  we  have  merely  a  slight  sensation 
of  discomfort,  but  those  of  the  loins  and  thighs* are 
really  painful,  having  been  vigorously  in  action. 

We  must  make  a  strong  distinction  between  exercise 
with  the  oar  and  that  with  the  paddle.  In  the  latter  exercise 
the  canoeist  derives  a  fixed  support  from  the  seat,  and  his 
legs  do  not  help  him  at  all.  They  usually  lie  in  the 
bottom  of  the  boat  inactive  and  extended.  As  to  the 
trunk,  it  participates  in  the  work,  not  by  movements  of 
flexion  and  extension,  but  by  lateral  displacements,  now 
to  the  right,  now  to  the  left.  Further,  the  canoeist,  when 
making  his  most  powerful  efforts,  is  not  leaning  back- 
wards, like  the  oarsman,  but  curved  forwards. 

This  position  is  imposed  by  the  necessity  of  giving  to  the 
movement  of  the  trunk  a  direction  opposed  to  that  in  which 
the  water  is  displaced  by  the  motor  of  the  boat.  Now  in 
paddling,  the  water  is  displaced  from  before  backwai  ds, 
whilst  in  rowing  it  is  displaced  from  behind  forwards. 

If  we  attend  a  boat  race  and  compare  the  scullers 
with  the  canoeists,  w  e  are  struck  by  the  difference. 


EXERCISES  WHICH  DO  NOT  PRODUCE  DEFORMITY.      33 1 

The  canoeing  movement  is  certainly  very  graceful. 
The  body  leans  in  regular  rhythm  to  the  right  and  to 
the  left,  and  the  head  at  each  displacement  is  inclined 
in  the  opposite  direction  to  the  trunk,  by  a  series  of 
lateral  inflexions  of  the  cervical  vertebrae.  From  these 
two  opposed  but  compensatory  movements,  results  a 
wave-like  movement,  which,  added  to  the  rapid  gliding 
of  the  frail  bark,  forms  a  seductive  picture.  But  the 
canoeist's  back  is  curved  like  that  of  the  jockey,  and  his 
legs  remain  inactive.  Hence,  in  our  opinion,  the 
inferiority  of  canoeing  from  the  hygienic  point  of 
view.  It  leaves  the  lower  limbs  absolutely  motionless, 
and  it  tends  to  produce  a  round  back. 

In  rowing,  the  oarsman  also  leans  forwards  at  intervals 
in  order  to  carry  his  oar  backwards,  but  this  is  at  a  stage 
in  the  exercise  when  no  force  is  required  and,  therefore, 
no  pressure  is  exercised  on  the  vertebrae.  The  really 
energetic  muscular  action,  the  one  which  determines  the 
progression  of  the  boat,  is  performed  by  bending  the 
body  backwards  ;  at  this  moment  of  the  effort  the  head 
is  high  and  erect,  and  if  the  movement  is  very  powerful, 
the  face  is  upturned.  The  really  active  movement  in 
rowing  consists  in  extension  of  the  dorsal  spine.  No 
movement  is  more  fit  than  this  to  remedy  a  round  back. 

It  will  be  w^ell  to  point  out  the  difference  between 
"sculling"  and  "rowing."  In  the  latter  case  there  is 
one  oar  held  in  both  hands,  which  forces  the  oarsman 
to  lean  to  the  side  of  his  oar.  In  sculling  there  is  needed 
an  equal  and  sym.metrical  effort  of  both  hands.  Hence, 
to  preserve  the  straightness  of  the  body,  sculling  is  much 
superior  to  rowing. 

II. 

We  cannot  review  here  all  the  exercises  which  are  able 
to  favour  regular  development.  But  we  should  like  to 
try  to  define  certain  points  which  must  be  kept  in  mind 
when  we  wish  to  appreciate  the  influence  of  movements 
on  bodily  form. 

First,  the  body  left  to  itself,  without  being  subjected 
to  any  external  influences  capable  of  producing  deformity^ 


332  PHYSIOLOGY    OF    BODILY    EXERCISE. 

tends  naturally  to  develop  in  a  regular  direction.  The 
causes  which  tend  to  produce  deviation  may  be  of  in- 
ternal origin,  such  as  affections  of  bones  or  joints,  retrac- 
tion of  tendons  or  of  muscles,  and  paralyses.  But  the 
most  common  deformities  arise  from  external  causes,  such 
as  pressures,  shocks,  works  or  habits  leading  to  a  vicious 
carriage.  Amongst  the  external  agents  capable  of  pro- 
ducing bodily  deformity,  ill-chosen  or  ill-directed  exercise 
is  a  very  frequent  cause. 

The  vertebral  column  is  the  axis  of  the  body.  When 
it  is  normal  in  direction,  the  body  is  upright  and  the 
attitude  is  elegant.  Most  of  the  deviations  of  the  spine 
have  a  muscular  source,  and  arise  from  the  predominant 
action  of  the  muscles  which  draw  the  vertebrae  in  a  given 
direction  over  those  which  should  balance  the  action  of 
these  by  drawing  the  spine  in  the  opposite  direction. 
Muscular  exercise  tends  to  develop  the  muscles  and  the 
bones  :  it  is  enough,  with  an  aesthetic  end  in  view,  that 
this  development  should  be  regular,  that  no  region  of  the 
body  should  acquire  an  exaggerated  size  capable  of  de- 
stroying harmony  of  proportion,  and  that  no  portion  of 
the  skeleton  should  assume  a  vicious  direction. 

Neglect  of  all  exercise  sometimes  coincides  with  devia- 
tions of  the  body,  but  these  are  almost  always  due  to  an 
habitually  vicious  carriage,  such  as  is  observed  in  persons 
of  sedentary  life.  The  schoolboy  kept  in  class  from 
morning  till  evening,  the  artisan  kept  all  day  in  the 
workshop,  often  present  deviations  of  the  figure  ;  but  the 
vicious  position  of  the  body  needed  for  writing  is  the  true 
cause  of  the  lateral  curvature  of  the  spine  which  is 
commion  in  school-children  ;  similarly  it  is  to  the  bent 
attitude  when  working  with  the  needle  that  we  must 
attribute  the  round  back  so  common  in  tailors. 

Certain  deformities  of  the  figure  may  be  due  even  to 
deficiency  of  exercise,  to  the  excessive  immobility  of  the 
individual  and  to  the  extreme  feebleness  of  the  muscles 
hence  resulting.  The  vertebrae  being  very  freely  movable 
on  each  other,  cannot  be  consolidated  and  acquire  the 
resistance  of  a  rigid  and  homogeneous  column,  without 


EXERCISES  WHICH  DO  NOT  PRODUCE  DEFORMITY.      333 

being  stronc^ly  pressed  to^^cther,  and  maintained  in 
intimate  contact  by  the  contraction  of  the  surrounding 
muscles.  If  these  muscles  are  too  feeble,  the  weii^ht  of 
the  shoulders  and  head  causes  the  vertebrae  to  glide  one 
upon  the  other,  in  the  direction  in  which  its  weight  tends 
to  carry  the  body,  that  is  forwards. 

When  muscular  force  is  completely  removed,  as  for 
instance  in  the  dead  body,  there  is  a  tendency  to  fall  for- 
wards ;  and  if  the  dead  body,  held  upright,  is  supported 
by  the  waist,  we  see  the  head  lean  down  towards  the 
chest,  the  shoulders  fall  forwards,  and  the  back  arched 
by  an  exaggerated  flexion  of  the  spine. 

This  stooping  attitude,  due  to  complete  absence  of 
muscular  action,  is  an  exaggeration  of  that  observed  in 
persons  whose  muscles  are  extremely  enfeebled  and 
atrophied  by  inaction.  The  round  back  is  in  these 
persons  always  accompanied  by  a  receding  chest,  first 
because  muscular  inaction  leads  to  diminution  in  the 
size  of  the  thorax,  secondly,  because  in  a  side  view  of 
the  body,  very  pronounced  convexity  of  the  back  tends 
by  comparison  to  cause  the  line  of  the  sternum  to  appear 
flat,  and  even  concave.  We  observe  this  characteristic 
deformity  in  all  cases  in  which  young  persons  have  led 
too  sedentary  a  life,  deprived  of  air  and  movement. 

Muscular  exercise,  in  whatever  form,  gives  marvellous 
results  in  these  deformities  in  which  we  cannot  properly 
speak  of  a  deviation  to  be  remedied,  but  rather  of  a 
weakened  part  to  be  supported.  The  vertebral  column 
promptly  finds  energetic  support  from  the  spinal  muscles 
as  soon  as  a  man  begins  to  perform  violent  movements, 
for  every  work  needing  a  certain  expenditure  of  force 
demands  action  from  these  muscles  for  the  purpose  of 
fixing  the  vertebral  column,  the  centre  and  pivot  in  all 
movements  of  the  trunk  and  limbs. 

But  aside  from  these  cases  of  excessive  debility,  it  is 
nni  from  increased  strength  of  the  muscles  that  we  must 
demand  the  means  of  restoring  perfect  uprightness  to  the 
figure.  The  persons  who  are  most  remarkable  for 
elegance  and  grace  are  often  very  S2ipple  rather  than  very 
vigorous. 

23 


334  PHYSIOLOGY    OF    BODILY    EXERCISE. 

Suppleness  of  figure  comes  from  the  great  ease  with 
which  the  vertebrae  can  glide  in  all  directions  over  each 
other.  From  this  great  mobility  results  the  facility  with 
which  the  various  pieces  of  the  dorsal  spine  accommodate 
themselves  to  the  different  attitudes  of  the  body,  and  to 
the  rapidity  with  which  the  trunk  is  balanced  in  all  the 
displacements  which  it  undergoes.  So  that  the  greatest 
possible  grace  of  figure  may  be  observed  in  clowns. 

Certain  exercises  which  demand  very  slight  expendi- 
ture of  muscular  force  have  a  remarkable  tendency  to 
make  the  back  very  straight  :  these  are  exercises  which 
need  balancing.  A  rope-dancer  cannot  keep  upright  on 
his  slender  support  if  he  allows  the  axis  of  his  body  to 
fall  out  of  the  vertical,  and  this  axis  is  represented  by 
the  vertebral  column.  All  the  movements  of  the  acrobat 
tend  to  give  to  the  muscles  which  move  the  vertebrae 
the  degree  of  contraction  necessary  that  the  bony  rod 
they  form  should  have  a  perfectly  vertical  direction. 

The  rope  dancer  preserves  when  on  the  ground  the 
position  which  his  well-disciplined  muscles  are  accus- 
tomed to  give  to  the  bones  on  which  they  act. 

Balancing  jugglers  are,  like  rope-dancers  and  india- 
rubber  men^  types  of  perfect  physical  straightness  ;  and 
if  we  compare  them,  in  the  circus,  to  the  gymnasts  whose 
specialty  is  the  trapeze,  we  are  struck  by  the  superiority 
of  the  former  in  elegance  of  figure. 

We  have  seen  nothing  more  charming  than  a  little 
balancing  girl  who,  at  the  circus,  climbed  to  the  top  of  a 
pyramid  built  of  bottles,  and  poised  herself  like  a  bird 
on  the  neck  of  the  highest  without  displacing  any  of 
them.  It  was  marvellous  to  see  the  child,  when  she  had 
built  the  fragile  structure,  first  make  sure  of  the  balance 
standing  upright,  then,  putting  her  foot  on  its  frail 
support  raise  herself,  holding  in  her  hand  the  neck  of 
the  last  bottle,  without  the  trunk  deviating  from  the 
vertical  by  a  millimetre.  It  was  then  necessary,  from 
the  stooping  posture,  to  gain  the  upright  one,  and  it  was 
only  by  a  mathematical  precision  in  the  contraction  of  the 
vertebral  muscles  that  the  extension  of  the  legs  and  thighs 
could  be  affected  without  upsetting  the  whole  structure. 


EXERCISES  WHICH  DO  NOT  PRODUCE  DEFORMITY.      335 

The  young"  girl  who  performed  this  extraordinary  feat 
had  gained,  by  practising  it,  a  most  graceful  figure,  and 
we  were  struck  to  see  the  contrast  between  her  and 
a  "gymnastic  woman  "  in  the  same  circus,  whose  back 
was  rounded  and  whose  shoulders  were  deformed  by 
practice  on  the  rings  and  trapeze. 

Straightness  of  the  spine  is  not  due  to  the  strength  of 
the  muscles  of  the  loins  and  back,  but  rather  to  their 
perfectly  harmonious  action.  If  the  muscles  which  bend 
the  spine  to  the  left  exceed  in  vigour  their  antagonists 
which  bend  it  to  the  right,  the  dorsal  part  of  the  spine 
yields  to  the  stronger  traction  and  there  is  a  tendency 
to  left  scoliosis^  however  great  the  strength  of  the  sub- 
ject. If  on  the  contrary  there  be  perfect  equality  ot 
strength  between  the  muscles  of  the  two  sides,  there 
will  be  harmonious  action  between  them,  and  the  figure 
will  be  straight. 

All  the  exercises  which  demand  perfectly  harmonious 
action  from  the  extensors  and  flexors  of  the  vertebrae 
tend  to  mkke  the  figure  perfectly  straight.  All  those, 
on  the  contrary,  in  which  there  is  predominant  action  in 
one  half  of  the  body  break  the  harmony  of  the  muscular 
forces. 

A  burthen  constantly  carried  on  one  shoulder  deforms 
the  figure  :  the  spine  deviates  to  the  opposite  side  of  the 
body,  the  muscles  of  which  are  obliged  to  contract 
vigorously  in  order  to  draw  the  trunk  to  their  side  and 
counterpoise  the  weight.  If  their  contraction  is  very 
prolonged  and  very  frequent,  they  undergo,  like  all 
muscles  the  action  of  which  is  too  prolonged,  a  short- 
ening which  keeps  the  spine  in  a  position  in  which  it 
has  too  frequently  been  placed.  The  vertebral  column 
deviates  and  the  shoulder  which  bears  the  burthen  rises. 
Warehousemen  who  carry  heavy  bales,  the  railway 
navvies  who  carry  sleepers,  have  the  left  shoulder  usually 
higher  than  the  right,  for  this  is  almost  always  the  one 
which  does  the  work.  The  "  carrying  "  shoulder  be- 
comes higher. 

If   the  burthen    is   carried   on   the   head,  two   things 


336  PHYSIOLOGY    OF    BODILY    EXERCISE. 

may  happen  :  either  the  load  is  excessive,  and  the  ex- 
tensors of  the  spine  support  it  with  difficulty.  The 
vertebrae  then  yield  to  the  pressure,  and  the  curves  of 
the  spine  are  exaggerated.     A  round  back  is  the  result. 

It  is  not  the  same  when  the  load  is  not  too  heavy,  and 
it  is,  as  is  usually  the  case,  balanced  on  the  top  of  the 
head.  The  vertebral  column  does  not  then  perform  a 
work  of  strength,  but  a  work  of  precision,  and  the 
porter  has  to  give  to  the  vertebral  column  a  direction 
which  agrees  perfectly  with  that  of  the  weight.  The 
axis  of  the  body  must  then  become  vertical,  and  there 
must  be  no  deviation  of  figure,  under  pain  of  displace- 
ment of  the  burthen. 

We  can  find  no  better  orthopaedic  exercise  for  a  child 
with  a  vicious  carriage  than  the  carrying  of  light  bur- 
thens on  the  head.  If  there  are  no  changes  in  the 
vertebrae,  if  the  deviation  of  the  spine  to  be  prevented 
or  remedied  is  due  solely  to  defective  harmony  in  the 
action  of  the  muscles  of  the  back,  this  balancing  exer- 
cise will  be  the  best  that  can  be  found  to  remedy  the 
nascent  deformity. 

Numerous  observers  have  pointed  out  the  elegance 
and  regularity  of  figure  in  country-women  who  carry 
vessels  of  water  on  their  heads  ;  and  how  on  the  con- 
trary there  is  deformity  in  those  parts  of  the  country  in 
which  the  pitcher  is  carried  on  the  shoulder. 

The  women  of  Teneriffe,  according  to  a  traveller  who 
visited  that  island,  are  remarkable  for  the  elegance  of 
their  figures  ;  their  skill  is  also  surprising  in  balancing  on 
their  heads  different  light  objects. 


PART    VI. 

THE    OFFICE    OF    THE    BRAIN    IN 
EXERCISE. 


OVERWORK  IN  SCHOOLS — MENTAL  AND  PHYSICAL 
EXERCISE  —  EXCITO-MOTOR  WORK  —  WORK  OF 
LATENT  STIMULATION— THE  WORK  OF  CO-ORDINA- 
TION IN  EXERCISE AUTOMATISM   IN    EXERCISE. 


CHAPTER  I 

"OVERWORK  IN    SCHOOLS." 

The  Scholastic  Regimen — Report  of  the  French  Academy  of 
Medicine.  "Mental  Overwork"  and  Sedentary  Lijc — Proposed 
Remedies  ;  A  more  Simple  course  of  Study,  and  more  Physical 
Exercise — How  these  Reforms  must  be  applied.  Their  Mutual 
Dependence — Difficulty  of  Simplifying  the  Course  of  Study. 
Dangers  of  more  Physical  Exercise  without  Diminution  oi 
Mental  Work — Are  Bodily  Exercises  Recreation  for  the  Brain 
— Unrecognised  Importance  of  care  in  the  Choice  of  all  Exercise 
for  the  Needs  of  Cerebral  Hygiene. 

A  HYGIENIC  question  of  the  greatest  interest  has  for 
some  years  attracted  the  attention  of  the  public  and  the 
profession.  We  are  alarmed  by  the  dangers  of  exces- 
sive v/ork  of  children  in  schools  and  academies,  and  the 
highest  authorities  have  pointed  out  the  sad  results  cf 
mental  overwork. 

The  French  Academy  of  Medicine,  officially  invited  to 
give  counsel  both  on  the  extent  of  the  evil  and  on  the 
nature  of  the  remedies  to  be  applied,  came,  after  an 
animated  discussion,  to  the  following  conclusions  : — 

"  Without  concerning  itself  with  the  course  of  study, 
of  which  however  it  desires  a  simplification^  the  Academy 
insists  specially  on  the  following  points  :  "  A  longer 
time  of  sleep  for  the  younger  children  :  for  all  the 
scholars  a  shorter  time  in  class  and  preparation,  that  is  a 
shorter  time  spent  in  sedentary  occupations^  and  a 
proportionate  increase  of  the  time  for  recreation  and 
exercise. 

"  The  imperious  necessity  of  making  all  the  scholars 
perform  daily  exercises  of  physical  training  proportional 
to    their   age    (walking,    running,   leaping,   formations, 


340  PHYSIOLOGY    OF    BODILY    EXERCISE. 

developments,  regular  and  prescribed  movements,  gym- 
nastics with  apparatus,  fencing,  games  of  strength,  etc.)"* 

The  French  Academy  of  Medicine  points  out  in  the 
existing  scholastic  regimen  two  different  faults  :  excessive 
mental  work,  for  it  desires  a  more  simple  course  of  study 
— and  insufficient  muscular  exercise,  for  it  advises  in- 
creased attention  to  physical  exercise. 

But  if  we  consider  the  actual  terms  of  the  resolutions, 
the  learned  assembly  does  not  appear  to  consider  the 
two  proposed  reforms  as  of  equal  urgency.  It  insists 
on  the  "  imperious  necessity  "  of  "  a  shorter  time  spent 
in  sedentary  occupations,"  while  it  rather  vaguely  ex- 
presses a  "  desire  "  to  see  a  more  simple  course  of  study, 
without  giving  any  definite  counsel  about  the  mental 
work  of  the  scholars. 

It  seems  that  the  members  of  the  learned  assembly 
have  especially  wished  to  decide  with  their  full  authority 
on  the  question  of  sedentary  life^  which  is  more  directly 
within  the  province  of  miedicine,  and  have  preferred  to 
leave  to  other  judges  the  care  of  deciding  whether  the 
children  really  perform  excessive  m.ental  work. 

We  may  then  hope  that  a  new  enquiry,  directed  by 
specialists,  will  allow  us  to  form  a  judgment  on  this 
question  of  mental  overwork  with  as  much  clearness  as 
the  French  Academy  of  Medicine  has  decided  in  the 
matter  of  physical  exercise. 

But  many  months  have  already  elapsed  since  the 
publication  of  the  Academy's  report,  and  no  step  has 
been  taken,  no  enquiry  has  been  officially  ordered.  The 
question  of  mental  overwork  after  having,  quite  rightly, 
excited  everybody,  seems  to  be  passing  into  oblivion.  It 
is  surrounded  by  silence,  as  if  everything  had  been  said. 

Must  we  then  consider  the  report  of  the  Academy  of 
Medicine  as  a  sufficient  guide  ?  If  it  were,  we  should  be 
tempted  immediately  to  apply  the  reform  which  it 
declares  to  be  most  urgent,  and  to  greatly  increase  the 
amount  of  bodily  exercise,  while  reserving  for  a  later 
reform  the  diminution  of   mental  work,  which  is  not  so 

*  Comptes  rendus  de  l'Académie  de  Médecine.     July  15,  1887. 


"  OVERWORK    IN    SCHOOLS."  34I 

Strongly   recommended,    and     the    initiation    of     which 
presents  moreover  much  more  serious  difficulties. 

In  fact  there  is  nothing  easier  than  to  impose  upon 
children  daily  exercises  of  training,  nothing  seems  more 
difficult  than  to  diminish  the  lessons. 

Intellectual  contest  is  now  the  commonest  form  of 
the  struggle  for  existence,  and  if  a  child,  letting  his  brain 
rest,  demand  from  it  merely  moderate  exertion,  he  risks 
being  beaten  in  the  race  by  rivals  who  are  more  re- 
gardful of  success  in  the  struggle  than  of  the  laws  of 
hygiene. 

Is  it  then  possible  to  apply  the  remedy  pointed  out  by 
the  Academy  as  an  urgent  necessity,  without  first  making 
the  reform  on  which  it  does  not  so  strongly  insist  ?  ^  Are 
we  to  increase  the  muscular  exercise  of  the  children 
even  in  cases  in  which  we  have  not  yet  "  simplified  the 
wurse  of  study  "  ?  Will  it  be  advantageous,  finally, 
to  make  children,  who  are  suffering  from  excessive 
mental  fatigue,  perform  a  "daily  regimen  of  physical 
training  "  ? 

The  academic  report  has  not  foreseen  this  question, 
and  here  is  an  unfortunate  want.  It  is  not  an  indifferent 
matter  whether  the  two  reforms  suggested  are  mutually 
indispensable,  and  whether  the  prescriptions  recom- 
mending exercises  of  strength  and  skill  are  addressed 
merely  to  children  who  lead  too  sedentary  a  life,  or  if 
they  also  apply  to  those  children  who  do  an  excessive 
amount  of  mental  vrork.  An  explicit  commentary  was 
so  much  the  more  needed,  because  already  the  general 
opinion,  in  advance  of  the  decision  of  the  judges,  had 
pronounced  in  favour  of  the  application  of  gym- 
nastic exercises  of  all  kinds  in  the  treatment -of  miental 
overwork.  A.11  those  who  have  appreciated  the  beneficial 
effects  usually  produced  by  ph3^sical  exercise,  seem  im- 
patient to  see,  while  waiting  for  other  reforms,  gymnastic 
teaching  take  a  larger  place  in  educational  establish- 
ments. 

If  we  believe  what  most  people  say,  bodily  exercises 
will  have  a  double  effect,  and  will  extend  their  benefits 
to  the  wearied  mind  of  the  child  as  well   as  to  his  en- 


342  PHYSIOLOGY    OF    BODILY    EXERCISE. 

feebled  body.  Muscular  exercise  will  be  a  salutary 
counterpoise,  able  to  re-establish  the  balance  of  the 
system  which  has  been  upset  by  excessive  mental 
effort. 

The  physiological  effects  of  the  most  common  bodily 
exercises  are  still  but  little  known,  for  they  are  seldom 
practised  by  men  who  study,  and  very  few  doctors  have 
had  the  opportunity  of  verifying  on  themselves  the  most 
interesting  results.  Amongst  the  effects  there  are  many 
which  are  purely  subjective — a  certain  phenomena  of 
fatigue,  for  instance — and  the  shades  of  which,  very 
characteristic  to  those  who  have  experienced  them,  may 
remain  a  dead  letter  to  the  ordinary  observer  in  whom 
they  have  never  occurred. 

Thus,  doubtless,  is  to  be  explained  this  widely  cir- 
culated error,  accepted  without  examination  by  most 
unscientific  persons,  and  even  by  some  doctors,  who 
attribute  to  physical  exercise  the  office  of  a  derivative 
from  mental  fatigue. 

Muscular  exercise  can  assuredly  remedy  the  faults 
of  scholastic  education  which  consist  in  an  excessive 
sedentary  life,  but  it  is  not  a  remedy  applicable  to  mental 
overwork.  There  is,  we  believe,  between  the  measures 
necessary  in  the  treatment  of  these  two  faults  of  education 
a  kind  of  antagonism  and  contradiction,  which  makes  the 
solution  of  the  problem  a  very  delicate  one. 

We  have  at  the  same  time  to  give  work  to  the 
inactive  muscles  of  the  child,  arfd  repose  to  his  over- 
taxed brain. 

Now  we  hope  to  show  that  in  certain  exercises  which 
the  Academy  recommends,  in  "the  regular  and  pre- 
scribed movements,  in  gymnastics  with  apparatus,  and 
in  fencing,"  the  intellectual  faculties  are  occupied,  and 
the  brain  has  to  work  just  as  much  as  the  muscles. 

If  then  it  is  proved  that  a  child  is  suffering  from 
mental  overwork,  how  can  we  dream  of  prescribing  these 
exercises  for  him  ? 

But  if  the  too  sedentary  life  of  the  scholar  imperiously 
needs  an  increased  amount  of  bodily  work,  and  if  we 
cannot  hope,  in  order  to  increase  the  time  for  exercise, 


"  OVERWORK    IN    SCHOOLS."  343 

to  diminish  the  hours  of  study,*  we  must  at  least  adopt, 
amongst  the  various  ways  of  exercising  the  body^  those 
which  need  least  the  association  of  the  brain  in  the 
muscular  work. 

No  one  has  at  present  attempted  to  examine  from 
such  a  standpoint  whether  it  is  necessary  to  exercise  dis- 
crimination in  choice  in  this  matter.  No  one  has.  asked 
if  the  gymnastic  methods  so  much  in  honour  in  these 
days,  are  those  most  capable  of  giving  to  the  muscles 
of  the  child  the  desired  activity,  without  imposing  fresh 
fatigue  on  his  already  overworked  brain. 

The  object  of  the  following  chapters  will  be  to 
establish,  on  a  physiological  basis,  the  rules  which  must 
guide  us  in  the  choice  of  an  exercise,  when  we  have  to 
deal  with  a  person  whose  life  is  too  sedentary,  and  who 
is  exhausted  by  continuous  mental  toil. 


*  M.  Edouard  Maneuvrier  in  his  remarkable  work  on  "  V Educa- 
tion de  la  Bourgeoisie^''  L.  Cerf,  1888,  proposes  a  complete  plan  of 
scholastic  reform,  according  to  which  it  will  be  possible  to  reduce 
to  six  hours  the  daily  work  of  the  child. 

How  many  years  shall  we  have  to  wait  before  so  urgently  needed 
a  reform  is  put  in  practice  ? 


CHAPTER  îî. 

MENTAL  WORK  AND   PHYSICAL   EXERCISE. 

The  Muscle  which  Works  and  the  Brain  which  Thinks — Similarity 
of  the  Physiological  Phenomena — Heating  of  the  Brain — Experi- 
ments of  Dr.  Lombard — How  of  Blood  to  the  Brain  during 
Mental  Exertion — The  Balance  of  Mosso — The  consequences 
of  Work  of  the  Mental  and  of  the  Physical  Order — Combustions 
and  Products  of  Dissimilation — Auto  Intoxications  through  Over- 
work. Similarity  of  effects  in  the  Physical  and  in  the  Psychical 
Order — Effects  of  Brain  Work  on  the  Composition  of  the  Urine  ; 
they  are  Identical  with  those  of  Muscular  Work — An  Attack 
cf  Gout  following  Mental  Fatigue  like  one  following  Physical 
Fatigue — The  Case  of  Sydenham. 

I. 

Leaving  all  philosophical  doctrines  on  one  side,  and 
moreover  without  any  need  for  committing  ourselves  to 
the  materialistic  hypothesis,  we  can  show  that  there  are 
very  close  analogies  between  mental  work  and  physical 
exercise.  These  are  two  modes  of  the  manifestation  of 
vital  energy  which  are  very  different  in  their  form,  but 
subject  to  the  same  physiological  laws. 

The  conditions  of  work  are  the  same  for  the  brain 
which  thinks  and  for  the  muscle  which  contracts  :  in 
both  of  these  organs,  when  their  activity  comes  into 
play,  we  observe  a  considerable  increase  in  the  blood- 
supply,  and  a  greater  production  of  heat. 

If  we  measure  a  limb  which  has  just  been  performing 
violent  exercise  we  ascertain  that  there  is  a  considerable 
increase  in  its  size.  This  is  because  its  vessels  are 
distended  by  an  increased  quantity  of  blood. 

It  has  even  been  noticed  that  the  brain,  when  at  work, 
becomes  the  seat  of  a  more  considerable  flow  of  blood. 
Some  physiologists  have  had  an  opportunity  of  studying 


MENTAL    WORK    AND    PHYSICAL    EXERCISE       345 

the  circulation  of  the  blood  in  the  cerebral  vessels  o( 
patients  in  whom  a  portion  of  the  skull  had  been 
removed  by  injury.  Through  this  species  of  window  to 
the  organ  of  thought  they  have  been  able  to  see  the 
brain  swell  with  blood  whenever  mental  work  was  per- 
formed, and  the  congestion  disappear  as  soon  as  the 
intellectual  effort  wan  over. 

An  ingenious  experiment  has  Qven  made  it  possible  to 
determine  in  a  very  striking  manner  that  the  (juantity  oî 
blood  drawn  to  the  brain  by  mental  work  is  more  or 
less  abundant  according  to  the  greater  or  less  intensity 
of  the  intellectual  effort.  Mosso,  an  Italian  physiologist, 
has  constructed  a  balance  on  which  a  man  can  lie  at  full 
length.  When  a  man  is  the  subject  of  experiment  the 
apparatus  is  so  counterpoised  that  the  part  which 
supports  the  head  and  that  which  supports  the  feet 
are  in  exactly  the  same  horizontal  plane.  The  sensibility 
of  the  balance  is  sufficiently  acute  for  a  very  light  weight, 
added  to  one  side  or  the  other,  to  destroy  its  equilibrium. 
If  the  person  under  observation  lies  down  perfectly 
motionless,  and  in  absolute  mental  repose,  the  two 
extremities  of  the  balance  remain  at  exactly  the  same 
level.  But  if  his  mind  becomes  occupied  with  ideas 
needing  an  effort  of  attention,  if  an  endeavour  is  made 
to  solve  a  difficult  problem,  if  a  call  is  made  on  the 
memory  or  the  judgment  ;  if  in  short  the  active  psychical 
faculties  come  into  play,  the  equilibrium  of  the  balance 
is  immediately  destroyed,  and  the  end  which  supports 
the  head  sinks. 

The  blood  flows  in  more  abundance  through  the 
cerebral  vessels  by  the  very  fact  of  mental  effort  ;  the 
brain  suddenly  becomes  heavier,  and  this  increase  in 
weight  gives  the  exact  measure  of  the  increase  in  blood- 
supply.  Vve  mxay  in  this  manner  determine  that  the 
lowering  of  the  head  is  more  marked  according  as  the 
psychical  faculties  are  more  strained. 

There  is  another  analogy  which  is  no  less  striking, 
between  the  work  of  the  brain  and  that  of  the  muscles. 
In  both  these  organs  greater  activity  of  function  is 
accompanied  by  greater  production  of  heat. 


34^  PHYSIOLOGY    OF    BODILY    EXERCISE. 

If  we  thrust  a  thermo-electric  needle  into  a  muscle  wc 
find  that  the  temperature  of  the  muscle  rises  when  it 
contracts.  This  heat,  detected  by  the  thermometer,  is 
but  a  small  part  of  that  which  has  been  produced  in  the 
motor  organ,  and  the  greater  part  of  which  has  been 
transformed  into  movement. 

We  know  in  fact  that  the  human  motor  is  subject  tc 
the  law  of  the  transformation  of  forces,  and  to  the  same 
conditions  as  ordinary  heat-engines  :  movement  cannot 
be  produced  without  consumption  of  heat.  The  perfect 
analogy  between  the  human  system  and  other  heat- 
engines  has  long  been  known.  The  quantity  of  heat 
expended  in  the  production  of  a  muscular  effort  of 
known  intensity  has  been  exactly  measured,  and  has 
been  found  to  be  nearly  equal  to  that  used  by  a  steam- 
engine  for  the  same  expenditure  of  force. 

Brain-work  can  evidently  have  no  common  measure 
with  the  mechanical  work  perform.ed  by  a  machine  or 
by  a  muscle  ;  but  physiology  has  shown  that  the  brain, 
like  a  muscle,  needs  for  its  activity,  a  certain  expendi- 
ture of  heat.  Mental  exertion  is,  like  muscular  exertion, 
accompanied  by  a  rise  of  the  temperature  of  the  working 
organ. 

This  truth  is  not  a  merely  imaginative  one.  Many 
years  ago  scientific  experiments  were  performed  to  show 
the  influence  of  brain-work  on  the  temperature  of  the 
head.  The  first  studies  in  this  subject  v/ere  made  by 
Dr.  Lombard  of  Boston  in  1869.  The  positive  results 
he  obtained  were  confirmed  by  the  labours  of  Schiff  and 
quoted  by  Dr.  Luys  in  his  work  the  Brain  and  its 
Functions.  It  is  now  admitted  on  all  hands  that  the 
brain  becomes  warmed  during  thought. 

Whether  the  will  uses  under  the  form  of  mental  work, 
or  under  the  form  of  muscular  exercise,  the  energy  con- 
tained in  the  human  system,  the  expenditure  mu^t 
always  be  liquidated  by  means  of  a  liberation  of  heat. 
Under  the  influence  of  certain  chemical  combinations 
which  go  on  within  the  organic  tissues,  and  which  are 
called  combustions^  the  heat  contained  in  a  latent  state 
within  the  molecules  of  the  body  is  set  free,  and  is  then 


MENTAL    WORK    AND    PHYSICAL    EXERCISE.      347 

absorbed   by  the  cerebral  or  the  muscular  action,  as  the 
heat  of  the  fire  is  absorbed  by  the  steam-engine. 

These  are  the  two  most  striking  analogies  which  meet 
the  physiologist  when  he  compares  bodily  with  mental 
work  ;  in  the  labourer  and  in  the  thinker  alike,  there  is 
an  increased  flow  of  blood  towards  the  organ  which 
woi-ks,  and  a  greater  liberation  of  heat  within  the 
anatomical  elemicnts  which  are  thrown  into  activity. 

II. 

If  we  carry  the  analysis  further,  we  find  that  there 
are  other  points  of  resemblance  between  the  results  of 
intellectual  work  and  those  of  physical  exercise. 

In  the  first  place,  in  the  brain  w^hich  thinks,  just  as 
in  the  muscle  which  contracts,  the  combustions  being 
more  active,  there  results  a  more  active  destruction  qj 
certain  living  materials  which  feed  the  combustions. 
It  is  in  the  same  way  that  a  locomotive  which  goes 
faster  must  increase  its  consumption  of  coals.  There  is 
a  certain  loss  in  the  system  as  a  result  of  mental  work 
just  as  in  the  case  of  bodily  exercise. 

But  this  is  not  all. 

The  combustions  do  not  cause  the  complete  disap- 
pearance of  the  substances  on  which  they  feed,  they 
change  them  in  nature  as  the  flame  of  a  fire  changes  the 
coal  and  wood  which  it  burns.  The  burning  wood  gives 
rise  to  products  of  combustion  which  may  be  found 
when  the  fire  has  gone  out,  which  are  cinders  and  soot 
Similarly  the  system  after  work  contains  products  of 
combustion,  called  products  of  dissimilation  because 
they  no  longer  resemble  the  tissues  of  the  organism  of 
which  they  once  formed  a  part. 

The  products  of  dissimilation — here  is  one  of  the 
most  interesting  points  in  the  history  of  work — are  in- 
jurious to  life,  and  must  be  discharged  from  the  system 
under  pain  of  producing  serious  disturbances.  Hence 
there  is  in  the  human  body  a  series  of  excretory  or  elimi- 
nating  organs,  charged  with  the  cleansing  it,  if  we  may 
use  the  expression,  of  all  these  impurities. 

But   if  the  formation  of  the  waste-products  of  com- 


348  PHYSIOLOGY    OF    BODILY    EXERCISE. 

bustion  is  very  considerable,  as  after  intense  work,  it 
may  happen  that  the  eliminating  organs  are  insufficient, 
and  that  the  products  of  dissimilation  accumulate  in 
excessive  quantity,  and  may  profoundly  disturb  the  great 
vital  functions. 

Now,  according  to  theories  which  arc  gaining  currency, 
and  in  support  of  which  we  have  brought  some  suffi- 
ciently striking  facts,  certain  forms  of  fatigue  are  due  to 
the  presence  in  the  blood  of  an  excess  of  the  products  of 
dissimilation  which  have  accumulated  owing  to  the 
combustions  of  work. 

When  fatigue  is  carried  too  far,  it  takes  the  name  of 
overzvork. 

Muscular  overwork  has  various  forms,  but,  amongst 
other  disturbances  it  may  produce  febrile  conditions 
analogous  to  typhus  or  typhoid  fever.  In  the  opinion  of 
all  physicians  in  these  days,  the  fevers  of  overwork 
which  are  observed  alike  in  animals  and  in  men,  are  due 
to  a  kind  of  poisoning  of  the  body  by  its  own  elements, 
to  an  auto-intoxication  of  the  system  by  the  products  of 
dissimilation  which  have  accumulated  in  too  great 
abundance  as  a  consequence  of  excessive  work. 

But  mental  overwork  also  leads,  according  to  several 
members  of  the  Academy  of  Medicine  (sitting  of  May 
7,  1887),  to  febrile  states  of  a  typhoid  character.  This 
similarity  of  effects  clearly  indicates  similarity  of  causes, 
and  shows  that  we  must  attribute  to  an  accumulation 
of  the  products  of  dissimilation  the  fevers  of  overwork 
derived  from  excessive  study,  as  well  as  those  which  are 
observed  to  follow  the  abuse  of  bodily  exercise. 

What  are  the  products  of  dissimilation  which  result 
from  brain-work  ?  We  cannot  exactly  say,  for  we  do 
not  even  know  the  exact  composition  of  all  the  organic 
products  which  are  formed  during  muscular  work,  a 
subject  which  has  received  much  more  attention  than 
brain-work.  We  merely  know,  according  to  the  most 
recent  labours  of  Gautier,  that  certain  poisons  analogous 
to  those  of  putrefaction  are  formed  under  the  influence 
of  the  chemical  actions  by  which  vital  heat  is  produced. 
What   relation   have   these   poisons,   which   are   of  the 


MENTAL    WORK    AND    PHYSICAL    EXERCISE.      349 

nature  of  alkaloids^  to  mental  work?  What  even  is 
their  correlation  with  muscular  work  ?  These  are 
questions  on  which  light  has  not  yet  been  thrown. 

In  the  actual  state  of  science  we  can  only  recognise 
these  poisons  by  their  effects,  and  the  living  organism  is 
the  reagent  which  determines  their  presence  by  the 
disturbances  which  they  produce.  In  any  case,  the 
singular  resemblance  between  the  disturbances  of  health 
which  occur  after  excessive  mental  work  and  after  over- 
work of  the  muscles,  authorises  us  to  conclude  that  the 
causes  are  analogous. 

Physicians  have  long  recognised  the  injurious  influence 
which  overwork  has  on  the  diseases  to  which  man  is 
subject.  The  same  aggravating  action  is  attributed  to 
mental  overwork  as  to  physical  overwork  on  the  course 
of  acute  or  chronic  affections.  The  most  insignificant 
internal  affections,  as  well  as  the  simplest  external  in- 
juries, may  assume  a  very  serious  character  in  a  man  who 
has  performed  muscular  work  at  once  too  violent  and  toe 
long  sustained,  as  well  as  in  one  whose  brain  has  per- 
formed mental  efforts  too  intense  and  whose  intellectual 
strain  has  been  too  prolonged.  A  pneumonia  assumes  an 
infective  character  in  a  young  soldier  overworked  by 
forced  marches,  and  equally  so  in  a  boy  who  has  worked 
excessively  in  preparing  for  an  examination.  In  both 
cases  the  seeds  of  disease  fall  on  a  field  vitiated  by  the 
products  of  dissimilation. 

Thus,  while  waiting  for  science  to  furnish  a  full  and 
satisfactory  theory  of  mental  overw^ork,  the  facts  of 
observation  show  us  that  there  is  a  striking  analog}/  be- 
tween the  results  of  excessive  physical  exercise  and  those 
of  abuse  of  mental  work. 

There  is  as  strong  an  analogy  in  the  slighter  degrees 
of  fatigue  as  in  the  grave  cases  of  overwork. 

There  is  a  material  phenomenon  very  easy  to  observe, 
v/hich  has  long  attracted  the  attention  of  physiologists, 
and  which  accompanies  excessive  muscular  work  :  we 
refer  to  turbidity  of  the  urine.  This  turbidity  is  due  to 
presence  in  excess  in  the  urine  of  products  of  incomplete 
■    24 


350  PHYSIOLOGY    OF    BODILY    EXERCISE. 

combustion,  urates  and  uric  acid.  Now  the  same 
turbidity  which  is  observed  in  the  urine  after  a  forced 
march  very  often  follows  great  intellectual  strain  ;  we 
have  been  able  to  observe  it  in  ourselves  after  finishing  a 
chapter  needing  laborious  study. 

After  muscular  exercise  the  products  of  nitrogenous 
waste  of  the  muscles  are  eliminated  in  the  urine  in 
the  form  of  uric  acid.  Is  the  same  the  case  after 
brain  work,  and  are  they  the  imperfectly  burned  nitro- 
genous molecules  of  the  nervous  substance  which 
are  eliminated  from  the  system  ?  We  are  at  present 
unable  to  give  a  satisfactory  answer  to  this  question  ;  but 
we  can  put  forward  as  a  fact,  as  certain  as  it  is  curious, 
the  similarity  of  composition  between  the  urinary 
deposits  after  physical  exercise  and  after  mental  fatigue. 
In  both  cases  an  excess  of  urates  is  eliminated. 

This  identity  in  chemical  composition  is  not  the  only 
analogy  presented  by  the  waste-products  formed  by 
physical  work  on  the  one  hand  and  by  exaggerated 
intellectual  activity  on  the  other.  The  excessive 
production  of  these  two  kinds  of  waste-products  can 
produce  identical  disturbances  of  health. 

It  has  been  often  pointed  out  in  those  with  a  gouty 
diathesis  that  an  acute  attack  may  follow  excessive 
physical  fatigue,  and  physicians  attribute  such  an 
explosion  to  the  accumulation  of  uric  acid  in  the  blood. 

Now  it  has  been  proved  that  great  mental  strain, "such 
as  is  caused  by  a  course  of  excessive  brain-work, 
produces,  like  bodily  exercise,  an  increase  of  uric  acid  in 
the  blood,  and  determines  by  so  doing  an  attack  of  gout. 
If,  in  the  physical  order,  a  day's  hunting,  for  instance,  is 
often  followed  in  the  gouty  by  a  violent  attack,  many 
cases  have  also  been  quoted  in  which  a  like  accident 
occurs  in  consequence  of  excessive  mental  work.  A 
very  celebrated  case  is  that  of  Sydenham,  author  of  a 
valuable  treatise  on  gout,  who  suffered  from  his  first 
attack  immediately  after  finishing  his  book. 

Thus  the  facts  of  daily  observation,  equally  with 
physiological  deductions,  authorise  us  to   conclude  ttiat 


MENTAL    WORK    AND    PHYSICAL    EXERCISE.      35 1 

there  is  a  close  analogy  between  the  effects  of  mental 
fatigue  and  those  of  muscular  fatigue.  This  first  con- 
clusion should  be  already  enough  to  render  us  very 
circumspect  in  the  application  of  physical  exercise  to 
persons  suffering  from  mental  overwork. 

But  if  we  descend  to  details,  if  we  make  a  summary 
analysis  of  the  chief  exercises  in  general  use  in  our 
own  time,  we  shall  find  that  the  analogy  between  mental 
work  and  bodily  exercise  becomes  more  and  more 
striking.  In  the  difficult  movements  of  gymnastics,  in 
riding,  and  in  fencing,  we  shall  see  that  the  office  of  the 
brain  and  the  nerves  is  as  important  as  that  of  the 
muscles. 


CHAPTER  HT. 

EXCITO-MOTOR  WORK. 

< 

Necessary  association  of  the  Nerve-Cell  and  the  Muscular  Fibre 
in  Movements— Origin  of  Motor  Stimuli — Nerve-Centres — The 
Spinal  Cord  a  Centre  of  Unconscious  Movements,  the  Brain  a 
Centre  of  Voluntary  Movements — Office  of  the  Grey  Matter  of 
the  Brain — The  Dog  of  Professor  Goltz — A  counter-proof:  the 
Observation  of  Dr.  Luys — Muscular  Work  and  Nervous  Work 
in  Voluntary  Movements — Frequent  Disproportion  between  the 
Effort  of  Will  and  the  Muscular  Exertion — Conditions  which 
make  the  Relation  vary  between  the  Expenditure  of  Nervous 
Energy  and  the  Mechanical  Work  of  the  Muscles — Diminution 
of  Muscular  Irritability — Muscular  Fatigue. 

I. 

The  intimate  relation  which  exists  between  the  brain, 
the  organ  of  thought,  and  muscle,  the  instrument  of 
movement,  is  not  as  a  rule  sufficiently  recognised.  We 
wish  to  show  here  how  the  cerebral  cell  is  intimately 
associated  with  the  activity  of  the  muscular  fibre,  and 
how  the  intellectual  faculties  are  far  from  remaining 
inactive  during  the  performance  of  various  gymnastic 
movements  which  are  nowadays  in  high  fâ.vour. 

To  understand  the  importance  of  the  part  which 
work  of  the  brain  may  play  in  a  bodily  exercise  we 
must  first  get  an  exact  idea  of  the  organic  apparatus  by 
the  aid  of  which  movements  are  performed.  This 
apparatus  is  essentially  made  up  by  :  I  Nerve-centres 
in  which  the  motor  stimuli  are  elaborated  ;  2  Conduct- 
ing organs  charged  with  the  transmission  of  these 
stimuli  :  the  motor  nerves  ;  3  Organs  whose  office  it 
is  to  respond  to  the  stimuli  emanating  from  the  nerve- 
centres,  and  to  perform  movements  :  the  muscles. 

To  these  organic  agents  of  movement  we  must  add 


EXCITO-MOTOR     WORK.  353 

another,  as  unknown  in  its  essence  as  it  is  indispensable 
tor  the  performance  of  conscious  muscular  actions  :  the 
Will. 

The  Will  orders  and  the  muscles  execute  :  but  it  is 
important  to  understand  that  the  principal  aident  of 
movement  has  no  direct  relation  with  its  subaltern. 
The  will  needs,  for  the  transmission  of  its  orders  to  the 
muscle,  the  whole  complicated  chain  of  nerve-centres 
and  nerves.  When  we  wish  to  move  the  foot,  the  order 
of  the  will  sets  out  from  the  grey  matter  of  the  brain, 
passes  down  the  spinal  cord,  and  along  the  nerves  of 
the  leg  and  thigh.  It  is  only  after  it  has  traversed  this 
long  succession  of  cells  and  nerve-fibres,  that  the  vibra- 
tion produced  by  the  impulse  of  the  will  finally  reaches 
the  muscular  fibres  and  determines  their  contraction.  If 
in  this  course  the  nervous  impulse  finds  an  interruption  in 
the  continuity  of  the  conducting  tissues  ;  if  the  spinal 
cord  or  the  motor  nerve  are  cut,  the  stimulus  stops  at 
the  point  of  lesion,  and  fails  to  reach  its  destination  : 
the  muscle  does  not  act  notwithstanding  the  exertion  of 
the  will,  for  it  never  hears  the  call.  Thus  are  explained 
the  paralyses  of  movement  which  follow  lesions  of  the 
spinal  cord  or  of  the  motor  nerves. 

The  will  has  then  no  direct  action  on  muscle — nor  has 
it  any  such  action  on  the  motor  nerves,  nor  on  the  spinal 
cord. 

But,  on  the  other  hand,  muscle  has  no  power  of  its 
owm  and  cannot  act  spontaneously.  The  force  contained 
in  its  fibres  is  latent,  and  resembles  that  of  gunpowder. 
The  gunpowder  will  not  detonate  without  a  spark  ;  the 
muscle  will  not  contract  without  a  nervous  stiimtliis.  A 
work  of  nervous  stimulation  must  then  precede  the  work 
of  the  muscle. 

Experimentally  we  may  replace  the  nervous  agent, 
the  natural  stimulus  of  muscle,  by  artificial  stimuli,  of 
which  the  one  in  commonest  use  in  physiology  is  elec- 
tricity. The  phenomena  which  occur  on  electrifying  the 
organs  of  movement  are  quite  similar  to  those  of 
voluntary  contraction,  and  we  have  here  a  valuable 
analogy  which  allows  us  to  study  precisely  the  work  of 


354  PHYSIOLOGY    OF    EODILY    EXERCISE. 

the  muscles.  We  shall  have  to  appeal  to  this  remark* 
able  analogy  for  the  explanation  of  certain  phenomena 
of  bodily  exercises. 

In  the  living  man  the  stimuli  which  cause  the  muscles 
to  act  come  from  the  nerve-centres,  that  is  from  certain- 
parts  of  the  nervous  substance  which  are  endowed  with  a 
peculiar  energy,  and  which  have  no  need  to  borrow  their 
power  from  any  other  part  of  the  system.  There  exist 
two  nerve-centres  for  the  muscles  of  animal  life  :  these 
are  the  Spinal  cord  and  the  Brain. 

The  Spinal  cord  is  the  centre  for  reflex  stimuli  and 
unconscious  actions  :  we  shall  speak  of  its  office  further 
on.  The  Brain  is  the  organ  in  which  the  stimuli  sent  by 
the  will  to  the  muscles  arise.  It  is  solely  from  this 
organ  that  the  orders  transmitted  to  the  muscles  by  the 
nerve-fibres  set  out. 

The  will  acts  only  through  the  brain,  and  especial!)' 
on  the  thin  layer  of  grey  matter  which  forms  its  outer 
surface  and  which  is  the  essential  organ  of  thought  as 
well  as  the  indispensable  instrument  of  motor  stimuli. 

Curious  experiments  have  shown  that  the  removal  of 
the  grey  matter  of  the  brain  leads  to  the  abolition  of  all 
voluntary  action,  without  however  necessarily  causing 
death.  Professor  Goltz  in  i88i,  brought  from  Strasburg 
to  the  congress  in  London  a  dog  which  he  had  been 
able  to  keep  alive  after  having  removed  all  the  brain- 
substance.  The  animal  was  no  longer  capable  of  making 
any  voluntary  movement.  Like  an  automaton,  it  walked 
straight  forwards  v/ithout  ever  turning  aside,  without 
seeking  to  avoid  obstacles  placed  in  its  way,  against 
which  it  struck,  though  its  visual  faculties  were  intact. 
Its  muscles  had  not  lost  the  faculty  of  action,  but  they 
were  no  longer  directed  by  the  will,  and  were  no  longer 
under  the  influence  of  external  stimuli  ;  they  only  per- 
formed reflex  movements,  or  actions  which  habit  had 
rendered  automatic. 

By  the  side  of  this  experiment  of  Goltz  showing  the 
abolition  of  voluntary  movements  when  the  cerebral 
cortex  has  been  removed,  we  may  quote  another  obser- 
vation which  is  no  less  curious,  and  which  shows  by  a 


EXCITO-MOTOR     WORK.  355 

sort  of  coiintcrproof  that  the  grey  matter  of  the  brain 
atrophies  when  its  movements  are  aboHshed. 

"  I  have  been  able  to  demonstrate,"  says  Luys,*  "  that 
in  persons  who  had  undergone  amputations  at  a  distant 
date,  subjects  who  had  been  long  deprived  of  an  upper 
limb,  for  instance,  there  existed  certain  long  disused 
portions  of  the  brain,  coincident,  very  distinctly  localized 
atrophies.  I  have,  moreover,  demonstrated  that  the 
atrophied  regions  of  the  brain  are  not  the  same  in  the 
case  of  the  amputation  of  a  leg,  and  in  that  of  the  ampu- 
tation of  the  upper  limbs." 

To  understand  the  value  of  this  observation  we  must 
recall  the  fact  that  inactivity  of  an  organ  is  always 
followed  by  its  atrophy.  If  then  the  disappearance  of 
certain  muscular  movements  through  the  removal  of  a 
limb  leads  to  the  "  silence,"  and  in  consequence  to  the 
atrophy,  of  certain  regions  of  the  brain,  this  is  clearly 
because  the  functions  of  that  organ  are  intimately  asso- 
ciated w^ith  those  of  the  muscles  ;  tJie  brain  works  when 
the  body  acts. 

II. 

Thus  it  is  within  the  grey  matter  of  the  brain  that  the 
nervous  work  which  precedes,  provokes  and  accompanies 
all  voluntary  muscular  actions  is  produced. 

If  we  have  succeeded  in  expressing  our  ideas  clearly, 
the  reader  will  now  understand  that  every  voluntary 
movement  involves  a  double  expenditure  of  force,  or  in 
other  words,  a  double  work  :  a  work  of  the  muscle  w^hich 
contracts,  and  of  the  brain  which  excites  the  contraction. 

The  work  due  to  the  muscular  contraction  is  apparent, 
outwardly  visible,  and  may  be  measured  by  the  dyna- 
mometer. 

The  work  due  to  the  excitement  of  the  motor  cells  is 
a  hidden  work,  w^hich  cannot  be  determined  de  visu  and 
can  have  no  common  measure  with  muscular  work,  be- 
cause  its   nature    is   not   mechanical,   but  pJiysiological. 

*  Luys.  The  Brain  and  its  Functions,  p.  53.  Kegan  Paul, 
Trench  &  Co. 


35^  PHYSIOLOGY    OF    BODILY    EXERCISE. 

We  can  represent  it,  by  comparison,  in  a  sufficiently 
satisfactory  manner,  thanks  to  the  analogy  between 
nervous  and  electrical  phenomena.  If  we  suppose  a 
muscle  thrown  into  action  by  electricity,  the  chemical 
changes  which  go  on  in  the  battery  might  represent  the 
physiological  working  in  the  grey  matter  of  the  brain 
under  the  influence  of  the  will,  and  which  lead  to  the 
muscular  contractions  through  the  mediation  of  the 
motor  nerves,  just  as  the  electricity  of  the  battery  calls 
forth  the  contraction  through  the  mediation  of  metallic 
conductors. 

Thus,  the  nervous  work  which  precedes  every  volun- 
tary movement  has  its  seat  in  the  grey  matter  of  the 
brain,  and  a  cerebral  effort  corresponds  to  each  muscular 
effort.  The  cerebral  effort  is  itself  a  result  of  the  action 
exercised  on  the  nerve-elements  by  that  force  of  un- 
known nature  called  the  will.  Without  concerning 
ourselves  about  the  nature  of  this  force  which  brings  into 
play  the  activity  of  the  motor  nerve-cell,  we  shall  desig- 
nate its  action  during  muscular  work  the  Effort  of   Will. 

The  Effort  of  Will  is  necessary  in  order  to  excite  a 
muscular  contraction,  but  the  energy  with  ivhich  a  muscle 
contracts  is  itot  always  proportional  to  the  intensity  of  the 
voluntary  stimulus. 

This  is  a  point  of  great  importance,  and  we  wish  to 
discuss  it  here,  for  it  has  conclusions  which  are  of  great 
importance  in  the  practice  of  physical  exercise.  Many 
circumstances  can  need  an  increase  of  the  nervous  work 
without  a  corresponding  increase  in  the  mechanical 
work  performed  by  the  muscle  ;  often  a  very  powerful 
effort  of  will  is  followed  by  an  insignificant  muscular 
contraction. 

This  difference  between  the  intensity  of  the  nervous 
work  and  that  of  the  muscular  work  which  it  calls  forth 
is  very  striking  in  the  phenomena  of  fatigue.  Everyone 
must  have  noticed  that  a  fatigued  muscle  needs,  to  make 
it  go  on  working,  a  more  intense  effort  of  the  will  than 
one  which  has  been  at  rest.  What  an  amount  of  energy 
of  will  must  be  expended  to  hold  out  after  five  minutes 
at  arm's  length,  a  weight  which  was  at  first  held  without 


EXCITO-MOTOR     WORK.  357 

effort  !  The  muscular  work  has  not  increased,  for  the 
weight  is  always  the  same,  but  the  nervous  work  is 
doubled  because  the  fatigued  muscle  has  become  less 
irritable  and  must,  if  it  is  to  contract,  be  more  strongly- 
stimulated  by  th(i  nerve.  Hence  the  necessity  that  the 
will  should  produce  a  more  violent  vibration  in  the 
nerve-centres,  a  more  intense  disturbance,  the  effects  of 
which  arc  translated,  when  the  work  is  over,  by  a  kind 
of  enfeeblement,  of  temporary  prostration,  which  always 
follows  great  expenditure  of  nerve-force,  equally  in  the 
psychical  and  the  physical  order. 

It  is  easy,  with  the  aid  of  electricity,  to  imitate  experi- 
mentally all  the  phenomena  of  muscular  contraction,  and 
to  render  evident  the  disproportion  produced  by  fatigue 
between  the  quantity  of  force  expended  by  the  fatigued 
muscle  and  the  intensity  of  the  stimulus  which  it  re- 
ceives. If  we  stimulate  a  muscle  by  means  of  a  current 
of  graduated  intensity  and  fit  to  one  of  the  extremities 
of  this  muscle  a  dynamometer  indicating  the  force  with 
which  it  contracts,  we  observe  that  after  a  series  of 
contractions  the  muscle  becomes  weaker  although  the 
intensity  of  the  current  has  not  diminished.  In  pro- 
portion as  the  work  is  prolonged  the  response  of  the 
muscle  to  each  stimulus  becomes  more  and  more  feeble, 
and  finally  ceases  altogether.  If  we  now  gradually 
increase  the  intensity  of  the  current  we  see  the 
contractility  of  the  fibre  gradually  reappear,  and  the 
dynamometer  indicate  a  stronger  and  stronger  contrac- 
tion which  at  last  becomes  as  strong  as  it  was  at  first. 
But  the  current  is  now  stronger,  and  a  contraction  of  the 
energy  of  that  which  was  at  first  produced  by  a  current 
represented  by  the  figure  I  may  now  need  for  its 
production  a  current  represented  by  the  figure  2. 

The  necessity  of  drawing  from  a  muscle  all  the  vigour 
it  possesses  is  not  the  only  circumstance  of  physical 
exercise  which  needs  supplementary  nervous  work.  We 
shall  see  in  the  following  chapters  under  how  many 
difi"erent  forms  work  of  the  brain  is  added  to  work  of 
the  muscles  in  the  course  of  exercises  of  the  Body. 


CHAPTER  IV. 

WORK  OF  LATENT  STIMULATION. 

A  Cat  lying-in-wait  for  a  Mouse — Lying-in-wait  in  Animals. 
Nervous  Work  which  this  Action  needs — Identity  of  Certain 
Phases  of  Bodily  Exercise  with  the  Phenomenon  of  lying-in- 
wait — A  Fencing  Bout — Physiological  analysis  of  the  "  Direct 
Blow" — Fencers  who  have  "Quickness" — Readiness  of  Blow — 
Latent  Stimulation  of  Muscle  and  Diminution  of  the  Latent 
Period — Explanation  deduced  from  the  Discovery  of  Helmholtz 
— The  Office  of  the  Brain  in  Fencing — How  the  Fencer  betrays 
his  Intentions — Advice  of  Bazancourt.  Effects  of  Work  of  Latent 
Stimulation— Nervous  Fatigue  and  Intellectual  Fatigue — Nervous 
Fatigue;  its  Effects  on  Nutrition — Why  Cats  do  not  become  Fat. 

Have  you  ever  watched  a  sleeping  cat  suddenly 
awakened  by  the  nibbling  of  a  mouse  ?  It  starts  up 
and  pricks  up  its  ears.  Look  at  it  lying  in  wait  :  not  a 
muscle  moves.  In  its  absolute  immobility  it  seems  still 
to  sleep  ;  but  ils  bristling  whiskers  and  sparkling  eyes 
announce  that  a  more  intense  life  animates  its  outwardly 
inert  bod)'  ;  all  its  limbs  are  stretched  like  springs,  and 
its  muscles,  under  the  influence  of  powerful  nervous 
stimulation,  only  need  a  last  push  to  throw  them  into 
violent  action. 

When  the  mouse  appears  its  capture  is  instantaneous  : 
with  the  rapidity  of  lightning  the  animal  has  sprung  and 
given  a  deadly  blow  with  its  claws. 

To  obtain  this  sudden  transition  from  immobility  to 
action,  the  cat  had  prepared  its  muscles,  distributmg  to 
each  a  supply  of  nervous  energy,  keeping  them  as  it 
were  awake  in  an  intermediate  state  between  repose  and 
action.  In  physiology  we  give  the  name  of  latent 
stimulation  to  this  preparation  which  the  muscle  must 
undergo  to  become  more  fitted  for  instantaneous  obedience 
to  the  orders  of  the  will. 


WORK    OF    LATENT    STIMULATION.  359 

Latent  stimulation  of  the  muscles  is  an  expenditure 
of  force  which  eludes  all  mechanical  estimation,  for  it  is 
not  outwardly  translated  by  work  in  kilogrammetres  ; 
but  it  is  a  physiological  action  which  does  not  pass 
unnoticed  by  the  nervous  system,  and  which  must  be 
taken  into  consideration  in  the  analysis  of  a  bodily 
exercise.  When  a  cat  lies  in  wait  for  a  mouse,  the 
fatigue  of  the  chase  does  not  consist  in  the  bound  which 
the  animal  makes  to  seize  its  prey,  but  in  the  nervous 
tension  which  precedes  this  movement. 

We  have  an  opportunity  of  studying,  in  numerous 
hunting  animals  besides  the  cat,  this  very  interesting 
action  of  lying-in-wait.  In  hunting  dogs  training  and 
inheritance  have' caused  the  disappearance  of  the  second 
part  of  this  act,  which  is  its  natural  termination.  A 
thoroughbred  pointer  never  gets  beyond  the  stage  of 
lying  in  wait,  and  never  bounds  upon  its  prey,  but  its 
muscles  do  not  escape  that  latent  stimulation,  which,  in 
principle,  has  the  object  of  rendering  them  more  ready 
for  action,  and  which,  in  shooting  dogs,  has  been 
developed  into  a  peculiar  attitude  indicating  to  the 
sportsman  the  presence  of  game. 

Many  exercises,  and  these  common  ones,  need  a 
preliminary  preparation  of  the  movements  which  recalls 
in  a  surprising  manner  the  phenomena  of  "lying  in 
wait  "  ;  these  are  exercises  in  which  quickness  ass\imes 
the  character  of  suddenness.  Wlienever  the  muscles 
must  pass  instantaneously  from  immobility  to  action, 
and  that  at  the  precise  moment  when  there  is  the  best 
opportunity  for  the  movement,  a  very  intense  nervous 
work  must  precede  the  muscular  action  ;  the  brain  must 
submit  the  muscle  to  a  preparation  without  which  the 
organ  of  movement  would  not  be  ready  to  obey  without 
loss  of  time. 

To  elucidate  this  point  we  need  a  rather  subtle 
analysis  w^hich  wall  be  best  performed  with  the  aid  of  an 
example. 

In  a  fencing-bout  two  fencers  will  sometimes  watch 
each  other  closelv  for  several  minutes  without  making 
any  movement.     All  at  once  this  immobility  gives  place 


360  PHYSIOLOGY    OF    BODILY    EXERCISE. 

to  an  exceedingly  rapid  movement  :  one  of  the  fencers 
has  seen  daylight,  that  is  a  space  of  a  few  millimetres 
which  the  other  had  discovered  by  an  imperceptible 
displacement  of  his  hind,  and  the  foil,  moving  with  all 
possible  speed  at  the  very  moment  this  opportunity  was 
given,  strikes  him  full  in  the  chest.  This  is  one  of  the 
most  valued  thrusts  in  fencing,  and  those  who  perform  it 
successfully  are  reputed  to  have  readiness  in  attack. 

What  happens  in  this  very  short  space  of  time 
necessary  for  the  delivery  of  a  direct  blow  ?  The  fencer 
has  uncovered  himself,  his  opponent  judges  that  he  can 
reach  him  ;  in  a  moment  the  muscles  contract  and  the 
weapon  reaches  its  mark. 

There  is  nothing  more  easy  in  appearance  than  this 
movement  of  stretching  the  arm  out  straight,  while  the 
legs  violently  thrust  the  body  in  the  direction  of  the 
blow.  But  this  simple  blow  which  needs  neither  cunning 
feints  nor  delicacy  of  touch,  and  which  only  consists  in 
a  straightforward  extension  of  arm,  is  really  one  of 
the  most  difficult  attacks  of  fencing.  Like  a  cat  lying 
in  wait  for  a  mouse,  the  fencer  who  is  watching  his 
opponent  must  seize  for  attack  the  precise  instant  when 
the  opportunity  occurs,  or  his  chance  will  be  lost.  A 
man  must  be  a  fencer  himself  in  order  to  understand 
the  value  of  an  infinitesimal  fraction  of  a  second  when 
he  has  to  make  a  thrust  the  very  moment  a  chance  is 
given  him  :  the  conception  of  the  blow  and  its  delivery 
must  both  occur  in  the  duration  of  a  flash  of  lightning. 

We  call  the  sudden  extension  of  the  leg  which  throws 
forward  the  fencer's  body,  and  the  quick  movement  of 
the  arm  which  directs  his  foil  against  his  opponent,  a 
lunge.  Now  this  movement  cannot  take  place  without 
an  almost  instantaneous  obedience  of  the  muscles  to  the 
will.  We  call  the  aptitude  of  a  fencer  for  passing  in- 
stantaneously at  the  right  moment  from  absolute  im- 
mobility to  the  most  rapid  movement,  his  qnickiiess. 
Fencers  who  are  deficient  in  quickness  can  calculate  a 
blow,  and  can  recognise  the  precise  instant  when  it 
ought  to  be  delivered,  but  the  arm  and  leg  do  not  obey 
quickly  enough.     The  blow  may  have  been  conceived  in 


WORK    OF    LATENT    STIMULATION.  36 1 

time,  but  it  is  delivered  too  late.  "  Quickness  "  of  the 
inusclcs  and  instantaneous  movements  need  a  consider- 
able nervous  expenditure,  of  which  certain  physiological 
facts  give  us  an  explanation. 

A  muscle  docs  not  instantaneously  obey  the  order  of 
the  will.  This  discovery  was  made  clear  by  Helmholtz 
Kw  1850.  This  physiologist  showed  that  when  a  given 
point  of  a  motor  nerve  receives  an  electric  stimulus  an 
appreciable  interval  occurs  between  the  moment  of 
stimulation  and  that  of  contraction.  This  retardation 
in  the  muscle  is  partly  due  to  the  time  occupied  by  the 
stimulus  in  traversing  the  nerve  ;  but  taking  into  ac- 
count the  duration  of  this,  which  can  be  exactly 
measured,  we  find  that  there  remains  an  appreciable 
fraction  of  time  in  which  the  muscle  which  has  already 
received  the  stimulus  has  not  yet  begun  to  contract. 
Helmholtz  gave  the  name  of  latent  period  to  this  silent 
time  in  "which  the  motor  organ,  having  already  heard  the 
call  of  the  will,  has  not  y^t  responded  by  a  movement. 

Now,  various  circumstances  can  alter  the  duration  of 
the  latent  period,  and  render  more  or  less  speedy  the 
obedience  of  the  muscle  to  the  stim^ulus  which  it  re- 
ceives. The  most  efficacious  condition  for  shortening 
the  latent  period  is  increase  of  the  strength  of  the 
stimulus. 

Let  us  suppose  that  the  motor  organ  is  stimulated  by 
an  electric  current.  The  latent  period  being  two  hun- 
dredths of  a  second  with  a  current  of  known  intensity, 
its  duration  will  be  reduced  to  one  hundredth  of  a 
second  if  we  double  the  intensity  of  the  current. 

If  the  muscle  is  stimulated  by  the  Will,  the  same 
law  will  be  applicable  to  the  duration  of  the  latent  period, 
and  this  will  be  shorter  in  proportion  as  the  strength  of 
the  voluntary  stimulus  is  greater,  this  increase  of  the 
stimulus  being  represented  by  a  more  violent  disturbance 
in  the  nerve-cells  and  fibres.  The  Effort  of  Will  will 
then  be  more  intense  according  to  the  suddenness  with 
which  the  movement  has  to  be  performed,  whatever  the 
speed  of  the  actual  movement  and  the  intensity  of  the 
muscular  effort  which  determines  it. 


362  PHYSIOLOGY    OF    BODILY    EXERCISE. 

But  we  will  penetrate  further  into  the  study  of  this 
curious  phenomenon  of  the  "  latent  period."  The  muscle 
at  rest  may  be  compared  to  a  sleeping  servant,  who 
must  be  awakened  before  he  can  obey  the  orders  of  his 
master.  We  have  seen  that  too  feeble,  a  stimulus 
leaves  him  inert — still  asleep  as  one  may  say — on  the 
contrary,  a  powerful  shock  wakes  him  up  at  once,  and 
obtains  from  him  a  prompt  obedience.  The  same 
diligence  in  the  performance  of  the  order  could  be 
obtained  if  we  began  by  waking  him  by  means  of  a 
preliminary  call  ;  he  would  then  hold  himself  in  readi- 
ness to  execute  the  slightest  order. 

Now,  the  experiments  of  the  laboratory  have  shown 
us  that  by  subjecting  a  muscle  to  a  series  of  very  slight 
electric  stimuli  we  can  throw  it  into  a  peculiar  condition 
which  is  not  yet  action,  but  which  is  no  longer  repose, 
and  which  disposes  it  to  contract  without  loss  of  time  on 
receiving  an  energetic  stimulus. 

We  call  latent  stiuiulatio7i  this  condition  in  which  the 
muscle  has  become  more  irritable,  more  ready  to  obey, 
like  a  thoroughly  alert  and  attentive  servant  only  waiting 
for  a  sign  from  his  master  to  execute  his  orders. 

In  a  fencer  watching  for  the  moment  of  attack,  all  his 
limbs  are  in  this  physiological  state  which  is  one  neither 
of  repose  nor  of  movement.  But  this  kind  of  active 
immobility  can  only  be  obtained  at  the  price  of  a  con- 
tinuous nervous  expenditure,  an  incessant  stimulation 
emanating  from  the  grey  matter  of  the  brain. 

While  the  fencer  on  the  watch  has  all  the  appearance  of 
complete  repose,  his  brain  and  nerves  are  in  a  condition 
of  excessive  tension.  Like  a  Leyden  jar  being  charged, 
his  muscles  are  making,  in  a  manner,  a  store  of  nervous 
energy,  in  order  that  at  the  right  moment  the  will  may 
suddenly  determine  the  explosion  of  movement. 

Such  is  the  nervous  expenditure  necessary  for  a  simple 
direct  blow  delivered  with  readiness. 

This  expenditure  attains  sometimes  greater  propor- 
tions still  in  certain  phases  of  a  fencing-bout  in  which 
the  performance  is  necessary,  not  of  a  simple  and 
elementary  movement,  such  as  the  extension  of  the  arm 


WORK    OF    LATENT    STIMULATION.  363 

In  a  straight  line,  but  a  series  of  combined  muscular 
actions,  such  as  a  difficult  parry  followed  by  a  thrust. 
In  these  cases  several  complicated  movements  must  at  a 
given  moment  follow  each  other  rapidly  and  fuse  into  a 
single  muscular  action  equally  precise  and  sudden. 
Such  a  performance  in  fencing  then  assumes  all  the 
characters  of  an  intellectual  operation. 

After  having  "crossed  swords"  with  his  opponent, 
when  the  fencer  thinks  he  has  calculated  his  game,  it 
often  happens  that  he  invites  an  attack  with  the  inten- 
tion of  replying  to  it  by  a  certain  thrust  in  which  he 
excels.  He  makes  a  feint  of  exposing  himself,  and  if 
the  too-confident  opponent  attacks  in  the  opening 
offered,  a  rapid  parry  turns  his  foil  aside,  and  an  un- 
avoidable thrust  follows.  The  fencer  was  ready,  he  had 
the  parry  and  thrust  in  his  hand.  The  movement  was 
co-ordinated  in  advance,  and  a  series  of  muscular  con- 
tractions, often  very  complicated,  follow  in  perfect  order, 
with  an  irreproachable  precision,  and  a  lightning-like 
rapidity. 

This  work  oi preliniiiîary  co-ordii.ation  needs  a  great  ex- 
penditure of  nerve-force.  Any  one  w  ho  has  ever  handled 
a  foil  will  remember  how  excessive  is  the  tension  of  the 
nervous  system  in  a  man  waiting  for  the  right  moment 
in  which  to  deliver  a  thrust  which  he  has  long  premedi- 
tated. To  understand  this,  a  man  must  himself  have 
experienced  the  internal  effort  which  keeps  his  muscles 
constantly  under  stimulation  strong  enough  to  make 
them  more  ready  to  obey,  but  not  strong  enough  to 
throw  them  into  action  till  the  right  moment.  And  the 
chance  which  must  not  be  allowed  to  escape  only  lasts  a 
fraction  of  a  second  ! 

Is  not  this  "  head  "  work  which  keeps  till  the  oppor- 
tune moment  the  mind  of  the  fencer  occupied  with  the 
idea  of  the  complicated  movement  which  he  wishes  to 
make,  and  which  makes  visible  in  his  imagination  the 
lines  which  his  foil  is  about  to  describe  ? 

Between  the  moment  when  he  has  co-ordinated  his 
parry  and  thrust  and  that  in  which  he  finds  the  oppor- 
turity  of  executing  them,  he  has  made  many  movements, 


364  PHYSIOLOGY    OF    BODILY    EXERCISE. 

has  practised  many  feints  in  the  endeavour  to  ensnare 
his  opponent  ;  but  in  the  midst  of  these  movem^ents,' to 
which  he  has  to  give  a  sustained  attention,  he  has  always 
kept  his  parry  and  thrust  m  his  hand,  awaiting  a  favour- 
able opportunity. 

He  is  like  a  man  wishing  to  use  a  telling  phrase,  who 
waits  for  an  opportune  moment,  follows  the  conversa- 
tion, and  directs  it,  and  while  speaking  never  ceases  to 
have  the  words  he  wishes  to  use  on  the  tip  of  his  tongue. 

But  the  most  lively  repartee  loses  its  effect  if  it  just 
misses  its  point  ;  similarly  the  most  cunning  thrust 
cannot  succeed  unless  it  is  delivered  at  the  right  moment. 
If  the  attention  of  the  fencer  is  relaxed  for  a  single 
instant  ;  if  the  muscles  which  have  to  deliver  the  blow 
cease  for  a  fraction  of  a  second  to  receive  a  latent  stimu- 
lation from  the  brain,  the  fencer  no  longer  has  his  move- 
ment "in  his  hand."  And  if,  at  this  moment,  he  has  an 
opportunity  of  delivering  the  thrust  he  has  prepared,  he 
finds  that  his  muscles  are  no  longer  ready  to  obey  in- 
stantaneously the  order  of  the  Will,  the  movement  has 
not  the  suddenness  and  readiness  which  are  needed  to 
ensure  its  success. 

It  is  only  at  the  price  of  most  fatiguing  efforts  that  a 
fencer  can  thus  keep  his  muscles  alert,  and  ready  for 
action,  all  the  time  that  he  is  hindering  them  from  acting 
till  the  right  moment  comes. 

The  Baron  de  Bazancourt  *  has  pointed  out  a  way  of 
divining  the  favourite  parry  and  thrust  of  an  adversary, 
the  one  he  has  in  his  Jimid.  He  advises  the  pretence  of 
a  very  lively  attack  by  extending  the  arm  and  thrusting 
the  body  vigorously  forwards,  keeping  up  such  a 
defence  as  not  to  be  exposed  to  a  thrust.  The  result  of 
this  false  attack  is  to  call  forth  an  instinctive  manifesta- 
tion of  the  movement  which  the  opponent  had  prepared. 
The  muscles  of  the  arm,  which  for  some  minutes  were 
undergoing  an  intense  work  of  latent  co-ordination,  spring 
into  action,  through  an  involuntary  movement  to  turn 
away  the  point  of  the  adversary's  sword,  although  this 

*  Bazancourt.     Les  Secrets  de  l'Epée. 


WORK    OF    LATENT    STIMULATION.  365 

never  reaches  its  destination.  His  foil  describes  in  the 
air  a  rapid  evolution  which  nnakes  it  possible  to  see  what 
movement  the  fencer  had  in  his  mind. 

The  complicated  movement  which  is  thus  involun- 
tarily produced  was  prepared  in  the  muscles  of  the  arm, 
as  the  phrase  which  an  actor  has  to  use  is  stereotyped  in 
his  brain  ready  to  be  spoken.  Just  as  the.  fencer  who 
is  too  impressionable  will  allow  the  inopportune  escape 
of  the  long  premeditated  movement,  so  an  excited  actor 
does  not  always  await  the  end  of  the  speech  he  has  to 
answer  before  beginning  the  reply  with  which  his  mind 
is  occupied. 

The  work  of  latent  co-ordination  which  we  have  endea- 
voured to  analyse  recurs  in  all  the  exercises  which  imply 
a  contest,  fencing,  single-stick,  boxing  ;  and  to  get  an 
exact  idea  of  the  expenditure  of  force  in  such  exercises 
we  must  not  merely  think  of  the  energy  of  the  muscular 
movements,  but  m.ust  also  take  into  account  the  expendi- 
ture of  nervous  energy. 

By  the  side  of  the  muscular  force  used  in  producing 
the  movement  we  must  further  write  down  the  nervous 
force  expended  in  shortening  the  time  from  the  moment 
when  the  movement  is  willed  to  that  when  it  is  per- 
formed ;  besides  the  motor  stinmlatmi  which  is  out- 
wardly translated  by  a  muscular  contraction,-  we  must 
take  note  of  the  latent  stiinulatio7i  which  leaves  the 
muscle  in  a  condition  of  apparent  repose,  but  which 
prepares  it  to  respond  instantaneously  to  the  call  of  the 
will. 

If  we  wish  to  express  this  conclusion  in  a  manner 
which  is  less  scientific  but  more  impressive,  we  may  say 
that  these  exercises  are  performed  rather  by  the  nerves 
than  by  the  muscles. 

Hence  result  the  very  peculiar  effects  of  these  exer- 
cises on  the  nervous  system. 

Every   one   must  have  noticed  that  after  a  difficult 

fencing-bout  the  fatigue  he  experiences  seems  dispropor- 

tioned  to  the  quantity  of  work  he  has   performed.     The 

fencers  who  seek  for  "  readiness  of  blow  "  make  no  very 

25 


366  PHYSIOLOGY    OF    BODILY    EXERCISE. 

violent  movements  ;  their  play  is  sober  :  they  watch 
more  than  they  act.  But  they  are  much  more  tired  by 
their  attentive  immobility  than  novices  who  gesticulate 
and  jump  about,  performing  all  kinds  of  fantastic 
movements. 

In  fencing,  the  expenditure  of  force  consists  less  in 
the  performance  of  muscular  actions  than  in  their  pre- 
paration. 

Fencing  is  therefore  the  type  of  the  exercises  which 
fatigue  the  nerves  more  than  the  muscles. 

If  beginners  say  that  they  at  first  experienced  pains 
all  over  the  body,  this  is  because  stiffness  is  inevitable 
after  any  unusual  exercise.  But  an  experienced  fencer 
never  feels  the  bruising  of  the  muscles  which  always 
follows  exercises  of  strength.  On  the  other  hand,  he  can- 
not escape,  after  a  difficult  bout,  a  kind  of  temporary 
collapse,  a  characteristic  prostration  which  we  may  call 
nervous  fatig^ie. 

The  sensation  of  nervous  fatigue  is  very  different  from 
that  experienced  after  great  labours  which  merely  need 
an  expenditure  of  material  force,  and  after  exercises 
which  make  the  muscles  work  rather  than  the  nerves. 
This  sensation,  which  when  once  experienced  is  not  for- 
gotten, is  difficult  to  describe,  as  are  all  fine  sensations. 
If  we  try  to  give  an  idea  of  it  by  comparing  it  to  a  well- 
known  sensation,  we  may  say  that  it  resembles  the 
psychical  prostration  which  follows  any  sustained  effort 
of  the  will,  as  when,  for  instance,  we  have  long  striven 
against  submitting  to  the  will  of  another,  or  when  we 
have  energetically  directed  our  attention  to  the  solution 
of  a  difficult  problem. 

Nervous  fatigue  shows  variations  under  different  cir- 
cumstances and  in  different  constitutions.  It  is  usually 
characterised  by  a  kind  of  prostration  and  temporary 
depression,  but  it  may  also  show  itself  by  a  transient 
excitability  similar  to  that  which  is  observed  in  certain 
enfeebled  persons,  and  which  doctors  call  a  condition  of 
irritable  weakness. 

This  peculiar  form  of  fatigue  which  follows  exercises 
demanding  much  nervous  work,  is  due  to  the  disturbances 


WORK    OF    LATENT    STIMULATION.  367 

undergone  by  the  nerve-ccUs  which  preside  over  volun- 
tary motion,  just  as  intellectual  fatigue  is  due  to  in- 
creased activity  of  the  cells  which  are  concerned  in 
mental  work. 

Now,  these  two  classes  of  cells  are  situated  in  the  grey 
matter  of  the  brain.  It  is  then  in  reality  the  brain  which 
supports  the  fatigue  following  exercises  needing  a  great 
expenditure  of  nervous  energy. 

For  this  reason,  fencing  is  unsuitable  to  men  who 
study,  and  equally  so  to  children  who  work  their  brains 
to  excess,  and  it  is  the  last  exercise  we  should  advise  for 
very  excitable  temperaments,  unless  we  have  to  provide 
food  for  unoccupied  brains,  for  unquiet  spirits  whose 
activity  consumes  themselves,  failing  better  occupation. 
In  such  cases  fencing  may  become  a  precious  derivative, 
by  absorbing,  as  would  mental  work,  the  excessive  ner- 
vous force  which  was  tormenting  the  inactive  mind. 

Fencing,  like  all  exercises  which  produce  disturbances 
in  the  nervous  system,  is  a  most  valuable  exercise  to 
persons  who  wish  to  get  thinner.  Among  the  most 
important  functions  of  the  nervous  system  is  that  of 
regulating  nutrition  ;  so  we  see  all  fatigue  borne  by  the 
ne%es,  all  excessive  expenditure  of  nerve-force  lead  to 
diminished  energy  of  the  process  of  nutrition  and 
favour   the   opposite   process,   thereby   causing   loss   of 

weight. 

Psychical  disturbances,  sustained  emotions,  through 
the  waste  of  nervous  energy  which  they  occasion,  hinder 
the  nutritive  functions,  and  lead  to  loss  of  weight.  It 
is  by  an  identical  mechanism  that  the  same  result  is 
produced  after  exercises  needing  a  great  expenditure  of 
nervous  energy.  It  is  curious  to  see  how  animals  whose 
mode  of  life  necessitates  movements  similar  to  those  of 
fencing  have  the  privilege  of  escaping  obesity. 

Have  you  ever  enquired  how  it  is  that  cats  can 
combine  with  their  proverbial  idleness  such  great 
agility?  Muscular  inaction  leads  just  as  much  in  other 
kinds  of  animals  as  in  the  human  species  to  obesity  ;  the 
dog  which  does  not  hunt,  the  horse  kept  in  the  stable, 
become  fat  and  sluggish.     Wild  animals  even,  if  kept  in 


368  THYSIOLOGY    OF    BODILY    EXERCISE. 

a  cage,  where  they  are  forced  into  the  repose  of 
domestic  Hfe,  very  rapidly  lose  their  slenderness  of 
figure  and  their  ease  of  movement. 

Why  does  the  cat  escape  the  ordinary  law,  and  why, 
in  spite  of  the  fact  that  it  rarely  moves,  does  it  seldom 
become  fat  as  does  a  dog  or  horse  under  similar  circum- 
stances ?  It  is  because  its  immobility  is  not  that  of 
inaction,  and  its  nerves  are  working  while  its  muscles 
seem  at  rest.  Like  a  fencer  waiting  the  moment  to 
attack,  the  cat  is  constantly  ready  to  spring.  It  is 
always  watching  something  ;  a  rat,  a  fly,  or  a  joint  of 
meat.  A  drawing-room  cat  only  makes  three  or  four 
springs  in  the  course  of  a  day,  but  each  of  them  has 
been  preceded  by  two  or  three  hours  of  latent  work. 
When  we  believe  that  the  animal  is  engaged  in  a  happy 
dream,  it  is  meditating  a  capture,  calculating  the  distance 
of  its  spring,  and  holding  its  muscles  in  readiness  for 
anything  that  may  happen.  Hence  it  is  never  taken  by 
surprise.  If  a  little  bird  escapes  from  its  cage,  it  is 
caught  and  eaten  in  three  seconds.  The  cat  has  been 
watching  it  for  a  week  ;  when  it  seemed  asleep,  it  was 
lying-in-wait. 


CHAPTER  V. 

THE  WORK  OF   CO-ORDINATION   IN   EXERCISE. 

Difficult  Exercises — Skill  in  Exercises — Circling  the  Trapeze  — 
Apprenticeship  of  Movements — Precision  in  Muscular  Actions — 
Office  of  the  Brain  and  of  the  Psychical  Faculties  in  the 
Co-ordination  of  Movements — A  Dancing-lesson  —  Muscular 
Education — Economy  of  Muscular  Force  and  of  Nervous 
Expenditure  with  equal  Mechanical  Work — Improvement  of 
the  Muscular  Sense — St.  Vitus's  Dance — Hygienic  Use  and  Im- 
portance of  Difficult  Exercises — Persons  who  should  Refrain 
from  them  —  Error  usually  Committed  in  the  Choice  of  an 
Exercise. 

The  will  is  not  the  only  faculty  of  a  psychical  order 
which  is  concerned  in  the  performance  of  movements  ; 
its  office  is  limited  to  determining  the  muscular  action 
and  stimulating  the  muscle  ;  but  other  factors  must  come 
into  play  to  regulate,  direct,  and  measure  muscular 
actions. 

Every  movement  needs  the  intervention  of  a  great 
number  of  muscles,  and  each  muscle  must  contract  with 
a  definite  force  in  order  that  the  whole  work  may  lead 
to  a  precise  movement.  We  call  work  of  co-ordination 
the  operation  whose  object  it  is  to  choose  the  muscles 
which  must  participate  in  the  movement,  to  regulate  the 
respective  efforts  of  each  of  them,  by  distributing 
exactly  that  quantity  of  nervous  energy  which  is  necessary 
to  produce  a  contraction  neither  too  weak  nor  too  strong. 
This  work  is  performed  by  the  brain. 

We  call  those  exercises  difficidt  which  need  rather  a 
clever  co-ordination  of  movements  than  a  great  quantity 
of  work.     Riding,  fencing,  gymnastics  with  apparatus, 


370  PHYSIOLOGY    OF    BODILY    EXERCISE. 

are    difficult     exercises     and    need    more    skill     than 
strength. 

I. 

Seeing  with  what  ease  the  most  complicated  actions  of 
ordinary  life  are  performed,  we  should  be  inclined  to 
believe  that  each  muscle  had  its  function  fixed  in 
advance,  and  was  so  connected  with  the  will,  that  it 
would  be  enough  to  wish  to  displace  a  part  of  the  body 
in  a  certain  direction,  in  order  immediately  to  find  the 
muscular  group  on  which  the  duty  would  devolve.  We 
forget  that  the  most  ordinary  actions,  those  which  are 
performed  with  the  greatest  ease,  have  been  laboriously 
learned,  and  were  at  first  awkward  and  difficult,  before 
becoming  as  it  were,  natural  and  automatic,  through 
long  practice. 

Difficult  exercises  generally  need  attitudes  to  which  a 
man  is  unaccustomed,  new  movements  which  his  limbs 
have  never  before  practised.  A  new  apprenticeship  is 
necessary  to  learn  the  new  muscular  combinations. 
Certain  muscular  groups  which  have  long  been  used  to 
act  together  must  be  disunited  in  certain  gymnastic 
movements,  whilst  in  the  same  effort  other  groups  must 
be  united  which  have  never  before  been  associated.  A 
man  who  tries  to  walk  on  his  hands  is  obliged  to  seek 
attitudes  which  are  entirely  new  to  him,  and  to  make  in 
his  exercise  combinations  of  movements  and  balances  to 
which  his  body  has  never  before  been  adapted.  What- 
ever a  man's  strength,  he  will  not  succeed  at  first.  All 
the  energy  he  throws  into  his  muscular  efforts  cannot 
make  up  for  his  want  of  practice,  for,  in  the  case  given, 
skill  is  more  needed  than  strength. 

In  every  new  movement,  in  every  unknown  attitude 
needed  in  difficult  ^exercises,  the  nerve-centres  have  to 
exercise  a  kind  of  selection  of  the  muscles,  bringing  into 
action  those  which  favour  the  movement  and  suppressing 
those  which  oppose  it.  The  bones  on  which  the  muscles 
act  must  also  be  displaced  in  a  direction  perfectly 
adapted  to  the  performance  of  the  required  action,  for  a 


WORK    OF    CO-ORDINATION    IN    EXERCISE.       37 1 

suitable  inclination  of  these  levers  will  favour  the  action, 
while  an  unsuitable  one  may  render  it  impossible. 
Finally,  all  the  parts  in  action,  the  limbs,  the  spine,  or 
the  pelvis,  must  execute  with  precision  certain  displace- 
ments relatively  to  each  other  whose  resultant  is  an 
attitude  favourable  to  the  performance  of  the  exercise. 

When  we  endeavour  for  the  first  time  to  perform  a 
hitherto  unknown  movement,  it  seems  at  first  that  our 
muscles,  so  docile  in  the  ordinary  actions  of  life,  have 
become  rebellious  to  the  orders  of  the  will.  When  the 
muscles  finally  obey,  the  bony  levers  in  their  turn  seem 
to  refuse  to  move  in  the  desired  direction,  and  the  body, 
notwithstanding  our  most  violent  efforts,  will  not  assume 
the  attitude  we  wish. 

There  is  a  well-known  gymnastic  movement  called 
circling  the  trapeze.  Children  who  ha\-e  once  learned  it 
can  perform  it  with  the  greatest  ease,  and  it  needs  a  very 
slight  expenditure  of  strength.  It  consists  in  hanging 
from  the  bar  of  the  trapeze  by  the  hands,  and  then 
making  the  legs  and  body  pass  right  over  the  top  of  the 
bar,  continuing  the  movement  of  revolution  until  the 
body  has  returned  to  its  former  position. 

We  may  defy  the  most  robust  and  most  active  man  to 
perform  this  movement  the  first  time  he  tries. 

When  he  has  seized  the  bar  in  his  hands,  the  novice 
who  attempts  to  imitate  his  teacher  finds  himself  greatly 
embarrassed.  He  does  not  know  how  to  give  to  his 
trunk  the  movement  necessary  to  make  his  legs  pass 
round  the  bar.  At  this  moment,  amidst  his  muscular 
efforts,  the  would-be  gymnast  is  evidently  making 
cerebral  efforts  :  first  he  tries  one  muscle,  then  another. 
If  he  examines  his  own  sensations  he  will  find  that  he  is 
performing  work  of  a  psychological  order  ;  his  nerve- 
centres  are  seeking  the  solution  of  a  problem  which  may 
be  thus  formulated  :  What  muscles  must  he  contract  to 
make  his  trunk  change  from  the  vertical  to  the 
horizontal  position  ?  The  answer  to  this  question  is 
not  usually  found  till  after  many  trials  ;  but  it  is  almost 
a  surprise  when  the  problem  is  solved,  and  the  move- 


372  PHYSIOLOGY    OF    BODILY    EXERCISE. 

ment  îs  at  length  performed.  We  do  not  feel  that  we 
have  made  a  greater  effort,  but  that  we  have  made  an 
effort  of  a  different  kind  to  the  previous  ones.  The  will, 
after  trying  unsuccessfully  several  muscular  groups,  has 
at  length  been  able  to  group  together  those  which  were 
really  suitable  for  the  production  of  the  desired  effect. 

He  is  like  a  man  who,  having  long  sought  the  mechanism 
for  opening  a  secret  door,  at  length  puts  his  finger  on  the 
right  knob  and  relaxes  the  catch. 

The  analysis  which  we  have  just  made  has  allowed  us 
to  see  one  of  the  kinds  of  work  of  co-ordination  :  the 
performance  of  a  new  movement.  But  the  work  of 
the  nerve-centres  in  difficult  exercises  does  not  end  here. 
Besides  the  apprenticeship  of  movements  which  are 
unknown,  there  is  the  improvement  of  already  known 
movements. 

Many  exercises  need  very  great  precision  of  move- 
ments. We  have  no  longer  to  choose  the  muscles  which 
shall  act  ;  but  we  have  exactly  to  determine  the  in- 
tensity of  their  contraction,  in  order  that  the  limb  they 
move  may  neither  fall  short  of,  nor  overshoot,  its  mark. 
We  must  adapt  the  intensity  of  the  muscular  effort  to 
the  distance  to  be  traversed  ;  or  else  the  direction  of  the 
movement  has  to  be  more  precisely  determined  than  even 
its  distance. 

All  the  exercises  of  skill  need  this  work  of  adaptation 
of  movements  to  determined  distances  or  directions. 
Fencing,  boxing,  single-stick,  quarter-staff,  need  a 
perfect  weighing  of  the  fortes  composing  the  movement, 
for  the  resultant,  that  is  to  say,  the  final  direction  of  the 
arm  or  the  leg,  must  be  exact  within  a  few  millimetres. 

We  call  work  of  co-ordination  the  operation  the  aim 
of  which  is  thus  to  regulate  the  intensity  of  the  re- 
spective efforts  of  each  muscular  group,  distributing  to 
each  muscle  the  quantity  of  nervous  energy  necessary 
to  obtain  a  contraction  which  is  neither  too  weak  nor  too 
strong. 

This  work  differs  greatly  from  muscular  work  properly 
so-called,  and  rather  resembles  an  intellectual  operation 


WORK    OF    CO-ORDINATION     IN    EXERCISE.        2i7 1 

than  a  material  action.  It  needs  that  most  of  the 
psychical  faculties  and  the  most  delicate  parts  of  the 
nerve-centres  should  come  into  play.  We  cannot 
estimate  this  by  the  dynamometer,  but  we  must  take  it 
into  account  if  we  wish  exactly  to  appreciate  the  force 
expended  by  the  worker. 

An  example  chosen  from  among  the  commoner 
phenomena  of  gymnastics  may  show  us  the  diversity  of 
the  intellectual  faculties  brought  into  play  in  the  work  of 
co-ordination. 

A  clown  is  about  to  jump  from  the  ground  on  to  a 
narrow  platform  of  considerable  height.  Watch  him 
preparing  his  movement.  He  remains  motionless  for 
an  instant,  as  if  hesitating  ;  his  lower  limbs  are 
alternately  flexed  and  extended  several  times,  re- 
hearsing the  violent  movement  he  is  about  to  make. 
He  is  calculating  the  effort  necessary  to  reach  the  plat- 
form without  passing  beyond  it.  The  greater  the 
precision  needed  in  the  leap,  the  more  apparent  is  this 
kind  of  preliminary  repetition,  which  is  the  translation,  to 
the  eyes  of  the  spectator,  of  the  work  going  on  inside  the 
acrobat.  Measuring  the  distance  with  his  eye,  he  is 
estimating  the  effort  necessary  to  traverse  it,  and  is  de- 
termining the  degree  of  contraction  which  he  must  give 
to  his  muscles. 

The  sensibility  of  the  muscles  and  of  neighbouring 
parts,  such  as  the  nerves  and  the  skin,  give  to  the  leaper 
an  exact  idea  of  the  intensity  of  the  contraction  he  is 
preparing,  the  memory  of  an  effort  which  he  has  often 
made  to  traverse  a  like  distance,  allows  him,  by  com- 
parison, to  judge  of  the  effort  he  is  about  to  make  ;  and 
it  is  only  after  this  rapid  calculation  that  he  makes  his 
spring. 

Thus  every  co-ordinated  movement  needs  the  action  of 
three  chief  faculties  :  Sensibility,  which  indicates  to  us 
the  intensity  of  the  muscular  work  ;  Judgment,  which 
enables  us  to  appreciate  its  probable  effect  ;  and  Will, 
which  decides  on  the  movement  and  determines  its 
performance. 

Generally,   muscular   actions  are  cc-ordlnated  during 


374  PHYSIOLOGY    OF    BODILY    EXERCISE. 

their  performance.  We  observe  this  in  slow  movementsx 
But  whenever  a  movement  must  be  very  prompt  and 
very  sudden,  it  must  be  co-ordinated  in  advance. 

Before  performing  an  action  needing  at  once  prompti- 
tude and  precision,  the  muscles  must  undergo  a  pre- 
paration. They  receive  from  the  nerve-centres  a  latent 
stimulation  too  feeble  to  make  them  contract,  but  suffi- 
cient to  keep  them,  as  we  may  say,  on  the  alert.  It  is  a 
warning  given  in  order  that  the  motor  organ,  like  a 
vigilant  sentinel,  may  do  its  duty  at  the  first  signal. 

It  is  only  at  the  price  of  this  constant  intervention  of 
nervous  energy  that  instantaneous  movements  can  be 
performed  with  just  measure  and  perfect  precision.  If  a 
muscular  action  were  at  once  very  sudden  and  entirely 
unforeseen,  it  would  have  a  character  of  disorder,  and 
would  be  ill-adapted  as  regards  intensity  and  co-ordina- 
tion, to  the  circumstances  which  called  it  forth. 

A  horse  frightened  by  an  unexpected  explosion  wishes 
to  make  a  bound  to  run  away,  but  its  muscles  are  un- 
prepared, its  limbs  cannot  instantaneously  assume  the 
desired  direction,  and  instead  of  springing,  the  animal 
falls  down. 

We  may  describe  in  one  word  the  character  of  difficult 
exercises  from  a  physiological  point  of  view,  by  saying 
that  they  need  above  all  work  of  co-ordination.  This  has 
for  immediate  effect  an  economy  in  the  expenditure  of 
force,  through  regulating  the  work  of  the  muscles, 
through  demanding  from  each  of  them  the  exact 
quantity  of  work  which  it  ought  to  perform  in  the 
exercise,  through  suppressing  useless  contractions, 
through  giving  to  the  bony  levers  the  most  favourable 
direction  for  the  performance  of  the  movement. 

The  faculty  of  co-ordination,  like  all  physiological 
faculties,  rapidly  improves  with  practice,  and  there 
results  great  ease  of  work  in  a  man  accustomed  to 
difficult  exercises.  With  an  equal  expenditure  of  force 
a  clever  gymnast  will  do  more  work  than  an  awkward 
one,  or  if  he  wishes,  will  do  the  same  work  with  the  ex- 
penditure of  less  force. 


WORK    OF    CO-ORDINATION    IN    EXERCISE.        375 

A  man  who  excels  in  exercises  of  skill  is  a  machine 
whose  yield  has  increased  ;  the  work  lost  is  in  him 
reduced  to  a  minimum. 

Ease  of  movement  is  a  quite  natural  consequence  of 
the  practice  of  different  exercises.  A  movement  is  easy 
when  nothing  hinders  or  opposes  it.  The  skilled 
gymnast  especially  excels  in  suppressing  every  muscular 
contraction  which  is  not  directly  favourable  to  the 
performance  of  the  movement.  In  the  movements  of 
an  awkward  man,  many  muscles  have  their  action 
paralysed  by  the  inopportune  intervention  of  antagonists. 
Much  of  the  force  which  he  expends  must  be  employed 
in  overcoming  the  resistance  which  his  own  muscles 
oppose  to  his  movements.  An  inexperienced  swimmer 
expends  force  enough  to  move  a  heavy  boat,  but  he  only 
swims  a  few  metres  before  he  is  exhausted.  His  dis- 
ordered efforts  come  from  a  useless  contest  between  the 
extensor  muscles  which  should  perform  the  movement, 
and  the  flexor  muscles  which  awkwardly  hinder  it. 

A  man  must  himself  have  practised  these  exercises  to 
understand  the  important  place  of  the  faculty  of  co- 
ordination. If  there  is  apprenticeship  of  unknow^n 
movements,  there  is  also  improvement  of  known  move- 
ments ;  there  is  method  in  walking,  method  in  running, 
method  in  raising  weights  with  the  expenditure  of  as 
httle  force  as  possible  ;  a  slight  movement  of  the  shoulder 
or  elbow,  a  curving  or  straightening  of  the  spine  are  move- 
ments which,  though  imperceptible  to  the  spectator,  may 
sometimes  diminish  the  work  by  one  half.  There  is 
only  one  way  of  understanding  all  these  refinements  of 
movement,  and  that  is  to  perform  them  in  person.  We 
then  understand  that  in  the  most  insignificant  muscular 
actions  there  are  numerous  variations  which  onlookers 
cannot  recognize.  By  practice  w^e  are  able  to  choose 
amongst  these  difficult  proceedings  and  we  naturally 
adopt  the  one  which  represents  the  greatest  economy  of 
force. 

It  is  thus  that  in  the  end  we  can  perform,  without 
fatigue,  exercises  which  at  first  seemed  most  fatiguing. 

The  dominant  feature  of  these  difficult  exercises,  that 


I'jG  PHYSIOLOGY    OF    BODILY    EXERCISE. 

which  it  is  important  to  bear  in  mind  in  the  therapeutic 
apphcaticn  of  exercise,  is  that  their  difficulty  diminishes 
in  proportion  as  they  are  practised.  So  their  effects  are 
very  different  when  they  are  performed  by  novices,  or  by 
men  aheady  broken  in  to  the  exercises  we  advise.  Certain 
athletic  exercises  which  need  at  the  outset  a  great 
expenditure  of  nerve-force,  are  performed,  after  a  certain 
time,  with  marvellous  ease. 

Riding  is  an  exercise  w^hich  shakes  and  wearies  the 
beginner  :  it  is  very  moderate  exercise  for  an  experi- 
enced horseman.  Rowing  needs  a  certain  apprenticeship, 
the  longer  because  it  is  often  practised  in  frail  boats  in 
which  it  is  difficult  to  balance,  such  as  the  skiff  and  the 
canoe  ;  but  after  practising  for  some  time,  nothing  is 
needed  but  plenty  of  muscle.  The  same  man  who  at 
first  was  exhausted  by  half-an-hour  at  the  oar,  wall  in  six 
weeks'  time  row  a  whole  day  without  fatigue. 

The  lessened  fatigue  in  exercises  which  are  diligently 
practised,  comes,  in  the  first  place,  from  a  more  intelli- 
gent use  of  the  muscles,  from  which  the  skilled  athlete 
gets  much  work  with  but  slight  expenditure  of  force. 
There  is  another  reason  for  feeling  less  fatigue,  because 
less  effort  is  required  from  the  nervous  system  for  the 
coordination  of  better  known  movements.  Work  which 
at  first  needed  the  constant  intervention  of  the  conscious 
faculties  is  later  performed  w^ithout  any  apparent 
cooperation  of  the  will  ;  it  has  become  automatic.  We 
must  not  compare  the  effects  of  an  exercise  a  man  is 
learning  with  those  of  one  which  he  know^s.  Dancing  is 
an  amusement  :  learning  to  dance  is  mental  as  well  as 
physical  work. 

We  have  before  our  eyes  the  picture  of  a  dancing 
lesson  taken  by  one  of  our  best  friends,  a  distinguished 
oculist,  who,  at  the  age  of  thirty  years,  wished  to  learn 
the  polka.  It  w^as  most  curious  to  see  how  the  contrac- 
tion of  his  face  indicated  an  extreme  tension  of  all  his 
faculties.  He  was  isolated  by  his  thoughts  from  all  his 
assistants,  concentrating  the  w^hole  power  of  his  will  on 
his  legs  which  refused  to  follow  the  rhythm.  It  was  a 
true  combat  amongst  his  undisciplined  muscles,  and  his 


WORK    OF    CO-ORDINATION    IN    EXERCISE.        377 

forehead  was  bathed  in  sweat.  Never,  he  afterwards 
informed  us,  had  a  cataract  operation  caused  him  a  like 
cerebral  effort. 

II. 

7'he  first  benefit  derived  from  the  practice  of  difficult 
exercises  is,  then,  in  the  education  of  movements. 
Everyone  has  noticed  how  rapidly  gymnastics  diminish 
the  awkwardness  and  clumsiness  of  the  man  who 
practises  them.  The  recruit  who  has  been  used  to  rough 
agricultural  labours  becomes  rapidly  vaorç:  polished.  His 
muscles,  hitherto  used  to  slow  obedience,  in  order  to 
perform  their  easy  movements  with  more  strength,  are 
obliged  to  obey  with  precision  and  rapidity.  They 
undergo  a  discipline  to  which  they  are  strangers,  and 
perform  an  apprenticeship  which  makes  their  action 
more  prompt  and  easy. 

If  we  consider  the  details  of  the  application  of  difficult 
exercises,  we  meet  certain  patients  for  whom  they  are 
strongly  indicated  :  these  are  children  suffering  from 
chorea.  In  this  disease  the  patient  has  lost  control  of 
his  muscles.  Involuntary  movements  disturb  him  from 
morning  till  night,  in  spite  of  all  his  efforts  to  remain 
motionless,  and  on  the  other  hand  his  voluntary  move- 
ments are  beyond  direction  and  control.  The  patients 
upset  things  they  touch,  they  wriggle  and  twist  when 
they  try  to  walk,  and  have,  in  a  word,  neither  precision 
nor  moderation  in  their  muscular  actions. 

Chorea,  or  St.  Vitus's  dance,  gives  us  the  opportunity 
of  studying  persons  whose  power  of  co-ordinating  move- 
ments has  disappeared.  To  re-establish  discipline  in 
their  insane  muscles  there  is  nothing  better  than  these 
exercises,  every  movement  of  which  needs  a  severe 
control  on  the  part  of  the  nerve-centres. 

But,  except  in  certain  very  special  cases,  difficult 
exercises  have  little  medicinal  application.  They  may 
be  a  useful  pastime,  and  may  become  a  wholesome 
passion  able  to  protect  a  young  man  from  dangerous 
temptations  :  they  can  give  to  a  man  a  feeling  of  self- 
confidence,  for  they  are  useful  in  defence  of  the  person  ; 


378  PHYSIOLOGY    OF    BODILY    EXERCISE. 

they  may  finally  turn  a  lout  into  an  agile  and  supple 
man,  but  they  will  never  make  a  weak  man  into  a  strong 
one. 

Every  exercise  tends  to  modify  the  system  in  a  sense 
favourable  to  its  own  performance,  and  to  create  types 
best  fitted  to  accomplish  it.  This  is  a  consequence  of 
the  physiological  law  in  virtue  of  which  function  makes 
structure.  It  is  enough  to  know  the  type  of  structure 
which  is  most  suitable  to  success  in  any  exercise  to 
conclude  that  the  practice  of  such  an  exercise  will  have 
a  tendency  to  modify  in  the  direction  of  such  a  type  the 
constitution  of  the  individual  who  gives  himself  up  to 
it.  Exercises  of  strength  tend  to  render  a  man  more 
massive,  those  of  speed  to  render  him  lighter.  We  may 
find  between  animals  and  men  analogies  of  structure 
which  correspond  in  a  striking  manner  to  analogies  of 
work.  The  porter  and  the  wrestler  are  built  like  the  ox 
and  the  cart-horse  ;  the  prize-fighter  resembles  the  bull- 
dog. If  we  enquire  the  results  of  difficult  exercises,  we 
find  a  striking  resemblance  between  a  man  who  practises 
them  very  much  and  the  animal  which  excels  in  them  ; 
the  acrobat  is  very  like  a  monkey. 

This  is  the  most  striking  result  of  difficult  exercises  : 
they  tend  to  make  movements  freer,  and  the  perform- 
ance of  work  more  easy.  But  just  because  of  the 
economy  of  force  which  results  from  the  skill  acquired, 
they  cause  less  than  others  an  association  of  the  great 
functions  of  the  economy  in  the  muscular  work.  By 
economising  the  force  expended,  they  tend  to  diminish 
the  expenditure  of  heat,  to  reduce  as  much  as  possible 
the  intensity  of  the  combustions  and  the  production  of 
carbonic  acid  which  results  from  them.  In  this  manner 
the  respiratory  need  is  but  little  increased,  and  there  is 
no  tendency  to  the  production  of  breathlessness.  For 
the  same  reasons,  the  circulation  of  the  blood  is  not 
quickened  nearly  so  much  in  exercises  of  skill  as  in 
exercises  of  strength  and  of  speed.  Difficult  exercises 
influence  very  little  the  activity  of  respiration  and 
circulation. 

On   the    other   hand,   these   exercises   have   peculiar 


WORK    OF    CO-ORDINATION     IN    EXERCISE.        379 

effects  on  the  nervous  system  which  arc  to  be  explained 
by  the  very  active  intervention  of  the  functions  of 
innervation  in  the  coordination  of  movements. 

If  we  consider  them  from  a  purely  hygienic  stand- 
point, we  may  say  that  difficult  exercises  are  far  less 
useful  than  exercises  of  endurance  or  exercises  of  speed. 
The  cases  in  which  the  physician  will  prefer  to  prescribe 
work  of  coordination  rather  than  work  of  strength  are 
very  rare. 

Increased  fineness  of  the  muscular  sense,  and  great 
dexterity  of  movements  may  have  their  value  in  certain 
circumstances  of  life.  It  is  no  doubt  sometimes  of  great 
practical  value  to  know  how  to  use  a  sword  ;  it  is  precious 
in  case  of  fire  to  be  able  to  climb  a  long  slender  cord  like  a 
monkey  :  it  is  agreeable  to  have  on  all  our  movements  a 
stamp  of  ease  which  makes  all  bodily  attitudes  graceful. 
But  hygiene  has  a  very  different  point  of  view.  The 
body  needs  for  complete  development  that  the  most  im- 
portant parts  of  the  human  machine  should  act  vigorously. 
Now,  exercises  which  develop  dexterity  tend  to  throw  the 
greater  part  of  the  work  on  the  most  delicate  parts  of 
the  human  system.  They  lead  to  economy  in  the  expen- 
diture of  muscular  force,  thanks  to  supplementary  work 
at  the  expense  of  the  nerves  and  the  brain. 

In  difficult  exercises  all  the  psychical  faculties  asso- 
ciate in  the  work  of  the  muscles.  Hence  arise  the  most 
characteristic  conditions  of  difficult  exercises  :  they 
need  brain-work.  Judgment,  memory,  comparison,  will, 
such  are  the  psychical  factors  which  preside  over  their 
performance.  The  cerebrum,  the  cerebellum,  the  sensory 
nerves,  are  organs  whose  very  active  concurrence  is  in- 
dispensable. 

Persons  whose  brains  have  already  been  heavily  taxed 
by  mental  work  are  not  then  those  to  whom  difficult 
exercises  are  suited. 

How  indeed,  can  we  expect  that  the  nerve-centres 
will  gain  repose,  and  the  cerebral  excitement  be  calmed 
under  the  influence  of  an  exercise  which  brings  the  en- 
cephalon  and  the  whole  nervous  system  into  action  ? 
This  is  however  a  frequent   error.      Difficult  exercises 


380  PHYSIOLOGY    OF    BODILY    EXERCISE. 

make  up  three-fourths  of  athletics.  All  the  exercises  per- 
formed with  apparatus  need  a  prolonged  apprenticeship. 
The  trapeze,  the  rings,  and  the  horizontal  bar  are  the 
terror  of  certain  novices  who  torture — not  their  muscles, 
but  their  brain — in  order  to  succeed  in  performing  a  diffi- 
cult movement,  which  in  the  end,  when  they  have  learned 
the  trick,  needs  little  work. 

Too  much  nervous  work  and  too  little  muscular 
work  !  This  is  the  reproach  which  clings  to  most  of  the 
exercises  which  need  a  long  apprenticeship,  and  which 
îire  those  most  practised. 


CHAPTER  VI. 

AUTOMATISM   IN   EXERCISE. 

Movements  Performed  without  the  Intervention  of  the  Brain-- 
Decapitated  Animals— A  Curious  Spectacle  Invented  by  the 
Emperor  Commodus— Organs  which  Perform  their  Functions 
Automatically— Unconscious  Movements— Office  of  the  Spmal 
Cord— Conditions  of  Automatism  in  Exercise  —  Influence  of 
Rhythm  ;  Movements  with  a  Cadence— Z>a?/a«^  Tunes— Influ- 
ence of  Apprenticeship— Necessity  for  Absence  of  Effort  m 
Automatic  Movements— Regularity  of  Automatic  Actions— A 
Personal  Observation  :  Automatism  in  Rowing— Persistence  of 
Automatic  Actions —  "  Memory  "  of  the  Spinal  Cord— How 
Different  Paces  are  Created— Tenacity  of  Early  Muscular  Habits 
—Quickness  in  Fencing— Race  Horses  Trained  too  Slowly— 
Effects  of  Automatism  in  Exercise  — Economy  of  Voluntary 
Nervous  Energy  —  The  Brain  supplemented  by  the  Spmal  Cord 
—Repose  of  the  Psychical  Faculties— Superiority  of  Automatic 
Exercises  in  Cases  of  Cerebral  Fatigue. 

We  have  tried  to  show  in  the  preceding  chapter  how  the 
brain  and  the  psychical  faculties  can  play  an  important 
part  in  bodily  exercises.  It  rennains  for  us  to  show  here 
that  muscular  work  may  sometimes,  on  the  contrary,  be 
performed  independently  of  the  brain  and  without  the 
intervention  of  the  will. 

We  must  first  recall  the  fact  that  the  brain  is  not 
indispensable  to  the  performance  of  certain  movements. 
The  spinal  cord  suffices  in  certain  cases  to  throw  the 
muscles  into  action,  for  it  is  a  nerve-centre,  and  conse- 
quently a  focus  of  independent  motor  activity.  _  But  the 
movements  due  to  the  unaided  action  of  the  spinal  cord 
have  a  peculiar  character  :  they  are  involuntary.  The 
will  in  fact  has  a  direct  action  only  on  the  cells  of  the 
brain,  and  cannot  influence  the  independent  activity  of 

26 


382  PHYSIOLOGY    OF    BODILY    EXERCISE. 

the  spinal  cord.  This  latter  is  only  excited  by  reflex 
actio7i. 

In  reflex  movements  the  will  is  no  longer  the  stimulus 
of  the  muscle  :  the  latter  contracts  under  the  influence 
of  a  sensory  impression. 

Let  us  suppose  that  an  afferent  nerve  is  aroused  by  a 
powerful  sensation.  The  excitement  is  conducted  by 
the  nerve-fibre  to  a  central  cell  in  the  spinal  cord,  from 
which  a  motor  nerve  arises.  This  cell  is  at  once  the 
termination  of  the  sensory  nerve  and  the  origin  of  the 
motor  nerve.  It  may  happen  that  the  sensory  impres- 
sion, instead  of  travelling  towards  the  head  to  awaken 
the  conscious  faculties,  stops  in  the  motor  cell  of  the 
spinal  cord.  The  latter  then  sends  it  on  as  a  motor 
stimulus  to  a  muscle.  The  impression  is  reflected  in  the 
motor  cell  of  the  spinal  cord,  as  the  sonorous  waves  of 
the  voice  are  reflected  from  a  wall  and  give  rise  to  an 
echo.  We  may  say  without  straining  the  analogy  that 
a  reflex  movement  is  the  echo  of  a  sensory  impression. 

In  general,  reflex  movements  are  very  simple  and 
seem  to  be  regulated  by  the  intensity  and  duration  of 
the  stimulus  which  excites  them — as  often  as  we  pinch 
the  foot  of  a  decapitated  frog,  so  often  is  there  a  slight 
flexion  of  the  limb — but  it  may  happen  that  reflex 
movements  are  more  complicated,  and  that  a  single 
stimulus  gives  rise  to  a  whole  series  of  muscular  actions. 
It  then  seems  that  a  simple  impression  awakens  in  the 
spinal  cord  the  memory  of  a  great  number  of  movements 
which  have  cften  been  performed  ;  just  as  a  single  word 
will  awaken  in  the  brain  the  memory  of  a  whole  series 
of  ideas.  Thus  the  contact  of  the  foot  with  the  ground 
will  produce  the  whole  series  of  the  movements  of  walk- 
ing. The  living  being  can  then  walk,  and  even  run, 
without  his  brain  taking  any  part  in  the  muscular  action. 

A  fact  of  Roman  history,  reported  by  Mosso  in  his 
book  on  "  Fear  "  gives  us  a  curious  proof  of  the  auto- 
matic power  of  the  spinal  cord.  The  emperor  Corn- 
modus  gave  to  the  people  of  Rome  a  spectacle  which 
was  much  appreciated.  He  -  let  loose  in  the  circus 
ostriches  which  were  excited    to  run,  and,  when  they 


AUTOMATISM    IN    EXERCISE.  383 

were  at  full  speed,  their  heads  were  cut  off  with  spears 
with  a  semilunar  end.  The  decapitated  animals  did  not 
fall  at  once,  but  continued  their  course  to  the  barriers  of 
the  circus. 

What  we  observe  in  a  decapitated  animal  running, 
gives  us  a  faithful  picture  of  what  is  going  on  in  an 
absent-minded  man  whose  legs  automatically  perform 
the  movements  of  walking,  while  his  brain  is  otherwise 
occupied  than  in  the  action  he  is  performing.  In  auto- 
matic movements  what  happens  is  that  a  series  of  reflex 
actions  are  substituted  for  actions  which  were  at  first 
voluntary.  The  brain,  after  having  combined  a  move- 
ment, and  determined  its  rapidity  and  rhythm,  seems  at 
the  end  of  a  certain  time,  to  delegate  its  powers  to  the 
spinal  cord  ;  it  little  by  little  loses  its  interest  in  the  per- 
formance of  the  action,  and  only  comes  into  play  when 
some  new  and  peculiar  circumstance  demands  a  change 
in  the  direction,  the  energy,  or  the  speed  of  the  move- 
ments. 

I. 

Automatism  is  the  faculty,  possessed  by  certain  nervous 
elements,  of  putting  the  muscles  in  action  without  the 
intervention  of  the  will.  Many  organs  of  the  body  have 
the  power  of  working  automatically  ;  the  heart  for 
instance  has  movements  over  which  we  have  no  control  ; 
the  frequency  of  its  beats  is  independent  of  our  will. 

Automatism  is  not  however  always  absolute,  and 
many  organs  can,  according  to  circumstances,  obey  the 
orders  we  give  them,  or  on  the  other  hand,  move  without 
our  being  aware  of  the  fact.  Thus  we  breathe  involun- 
tarily even  when  asleep,  but  we  can  at  will  quicken, 
slacken,  or  suspend  the  respiratory  movements. 

The  movements  of  the  muscles  of  animal  life  may 
present,  like  those  of  organic  life,  an  automatic  character. 
The  limbs  and  the  body  move  when  we  are  asleep  with- 
out the  intervention  of  the  will,  and  in  the  waking  state 
numerous  complicated  actions  are  performed  uncon- 
sciously. A  man  much  occupied  in  thought  will  get  up 
without  thinking,  walk  to  and  fro  without  noticing  it, 


384  PHYSIOLOGY    OF    BODILY    EXERCISE. 

and  perform  absently  numerous  movements  of  which 
he  has  no  remembrance.  These  are  automatic 
actions. 

The  movements  of  walking  are,  of  all  muscular  actions, 
those  which  most  easily  become  automatic.  Everyone  must 
have  noticed  how  easy  it  is  for  the  brain  to  be  otherwise 
engaged  and  to  take  no  part  in  the  work  of  the  legs 
when  we  are  walking  ;  we  can  discourse,  reflect,  and 
even  compose  verses  while  walking.  It  will,  however, 
be  difficult  to  help  thinking  of  the  muscles  in  action  when 
circling  the  trapeze,  or  fencing.  The  more  difficult  an  exer- 
cise, the  more  marked  the  intervention  of  the  will,  and  the 
more  mental  concentration  is  needed  in  its  performance. 
But  the  exercises  which  were  most  difficult  at  first,  come 
in  the  end  to  be  performed  automatically  by  practice. 
All  the  horsemen  who  pass  by,  rising  so  gracefully  in 
their  stirrups  at  each  step  of  the  horse,  perform  this 
movement  without  giving  it  the  least  attention,  and 
surrendering  their  bodies  to  an  entirely  automatic  move- 
ment. If  you  wish  to  know  how  their  brains  were 
exercised  when  they  were  learning  to  rise  in  their  stirrups, 
watch  a  novice  out  for  a  Sunday  ride  stiffly  perched  upon 
his  hired  hack,  endeavouring  in  vain  to  "  identify  "  him- 
self with  the  movement  which  jolts  him,  and  bearing 
witness,  by  the  contraction  of  his  face,  to  the  profound 
mental  strain  to  which  he  is  subject. 

The  first  condition  needed  for  an  exercise  to  become 
automatic  and  to  be  performed  without  any  effort  of 
attention,  is  that  it  should  be  perfectly  known,  and  that 
its  apprenticeship  should  long  ago  have  terminated. 

That  an  exercise  may  be  performed  without  the  inter- 
vention of  the  conscious  faculties,  several  other  conditions 
are  necessary,  and  in  the  first  place  the  absence  of  effort. 
We  know  that  effort  is  a  contraction  of  the  whole  body, 
whose  object  it  is  to  compress  energetically  all  the  bones 
of  the  skeleton,  in  order  to  form  of  these  various  mov- 
able pieces  a  rigid  whole,  able  to  give  a  solid  point  of 
application  to  the  muscles  in  action.  It  is  impossible  to 
preserve    perfect    freedom    of   mind    when    making   an 


AUTOMATISM    IN     EXERCISE.  385 

effort.  The  muscles,  obliged  to  contract  with  all  possible 
energy,  seem  to  turn  to  their  advantage  cerebral  nervous 
energy. 

A  man  who  puts  his  whole  strength  into  a  movement 
of  any  kind  feels  himself  completely  absorbed  in  his 
effort,  and  loses  temporarily  the  consciousness  of  what  is 
f^oing  on  around  him.  If  some  one  speaks  to  you  at 
the  moment  when  you  are  trying  to  measure  your  utmost 
strength  with  a  dynamometer,  you  only  preserve  a  con- 
fused recollection  of  the  words  which  fall  upon  your  ears, 
your  conscious  faculties  were  otherwise  occupied  and 
were  distracted  by  the  effort  :  so  true  is  it,  that  mental 
actions  and  muscular  actions,  although  so  different  in 
their  essence,  are  often  performed  with  the  aid  of  the 
same  instrument.  It  seems  that  the  brain,  an  instrument 
of  muscular  as  well  as  of  mental  work,  is  engrossed  by 
the  muscles  when  the  latter  have  to  employ  their  whole 
strength  ;  hence  thought  has  not  free  play,  and  cannot 
be  as  clear  as  usual.  This  taking  possession  of  the 
brain  by  the  muscles  explains  the  usual  want  of  intelli- 
gence of  athletes  and  of  men  who  do  heavy  work.  The 
brain  of  a  man  who  has  made  too  many  muscular  efforts 
is  a  blunted  tool  which  is  no  longer  fitted  for  mental 
work. 

There  are  then  two  essential  conditions  that  muscular 
work  may  become  automatic  ;  these  are  long  practice  in 
the  exercise  performed,  and  moderation  in  the  muscular 
effort  it  demands. 

There  are  many  other  circumstances  which  favour 
automatism,  and  allow  work  to  be  performed  without 
the  intervention  of  the  will.  The  subject  has  not  been 
as  yet  methodically  studied,  nor  has  any  one  hitherto 
endeavoured  to  deduce  from  this  curious  phenomenon  of 
automatism,  the  practical  conclusion  which  w^ould  be 
valuable  in  considering  the  hygienic  application  of  mus- 
cular exercise. 

There  is  a  fact  of  observation  which  is  difficult  to 
explain,  but  the  truth  of  which  every  one  will  admit;  this 


386  PHYSIOLOGY    OF    BODILY    EXERCISE. 

is  that  regularity  of  movements  tends  to  make  work 
automatic.  In  a  man  who  has  for  some  time  been  walk- 
ing at  a  uniform  pace,  the  conscious  faculties  no  longer 
preside  over  the  movement,  the  brain  is  no  longer  in 
command,  the  muscles  obey  a  series  of  reflex  stimuli 
which  start  from  the  sensation  produced  by  the  alternate 
setting  down  and  raising  of  the  foot.  The  more  regular 
the  reproduction  of  the  sensation  which  determines  the 
reflex  action,  the  more  exact  is  the  work  of  the  auto- 
motor  mechanism  which  determines  progression.  Every 
one  has  noticed  the  influence  of  rhythm  on  move- 
ments. There  are  musical  airs  which  *'  carry  us  away  "  ; 
their  well-marked  cadence  regulates  the  movements. 

The  sensation  which  strikes  the  ear  becomes  the 
starting-point  of  reflex  actions  which  lead  to  alternate 
movements  of  the  legs. 

Walking,  which  we  may  consider  to  be  the  type  of 
automatic  exercises,  needs  however  a  cerebral  effort  as 
soon  as  it  is  performed  under  circumstances  which  make 
it  irregular.  Every  walker  must  have  noticed  how  fa- 
tiguing it  is  when  we  have  to  "  choose  our  steps."  When 
we  pass  from  a  fissured  and  rocky  path  to  a  well-made 
high  road,  we  feel  great  satisfaction,  and  the  work  dimin- 
ishes by  one  half.  However,  if  we  analyse  the  exercise, 
we  see  that  walking  on  the  smooth  surface  does  not 
lessen  the  muscular  work,  but  that  it  no  longer  needs  the 
superintendence  of  the  brain.  On  the  rough  road  the 
brain  must  watch  with  a  vigilant  attention  every  move- 
ment of  the  legs.  According  to  the  irregularities  of  the 
road,  we  have  to  lengthen  or  shorten  our  pace,  to  place 
the  foot  precisely  on  a  stone  which  offers  a  solid  support, 
to  avoid  a  jagged  projection  or  a  puddle  of  water.  It  is 
nothing  but  walking,  and  walking  probably  more  slowly 
than'  on  smooth  ground,  but  it  is  no  longer  unconscious 
exercise,  and  the  brain  must  not  leave  the  muscles  to 
their  own  guidance  under  pain  of  a  false  step  and  a  fall. 
On  the  high  road  the  conscious  faculties  maybe  dormant 
as  far  as  the  exercise  is  concerned  ;  here  to  the  work  of 
the  muscles  is  superadded  a  work  of  direction  and  con- 
trol on  the  part  of  the  brain.     It  is  to  this  additional 


AUTOMATISM    IN    EXERCISE.  387 

work  that  the  excessive  fatigue  is  due.  Walking-,  in 
becoming  irregular,  has  lost  its  automatic  character,  and 
needs,  for  an  equal  quantity  of  muscular  work,  a  greater 
expenditure  of  voluntary  nervous  energy. 

How  are  we  to  explain  this  mysterious  influence  of 
regular  alternation  of  movements  on  their  automatic  per- 
formance ?  No  physiological  explanation  has  hitherto 
been  given,  but  numerous  practical  applications  are  daily 
made.  The  importance  of  cadence  and  rhythm  in  facili- 
tating movements,  and  in  diminishing  fatigue  by  relieving 
the  brain  of  the  care  of  directing  the  muscles,  has  always 
been  understood.  Music  and  dancing  have  always  been 
associated.  In  military  manœuvres  the  drum  relieves 
the  foot  soldier  from  the  necessity  of  attending  to  the 
movements  of  his  legs  ;  he  keeps  step  in  spite  of  himself. 

If  rhythm  and  cadence  tend  to  produce  automatism  in 
movement,  it  is  curious  to  notice  how  the  impulse  once 
given  to  the  limbs  is  regularly  and  uniformly  repeated 
throughout  a  long  period  of  timie.  When  the  performance 
of  the  muscular  action  has  once  been  handed  over  to  the 
automatic  powers  of  the  system,  this  action  tends  to 
remain  always  at  the  same  measure,  to  be  performed 
with  the  same  speed.  If  the  exercise  is  prolonged,  the 
last  movements  are  exactly  like  the  first. 

I  have  quite  recently  been  able  to  observe  on  myself 
this  remarkable  tendency  of  unconscious  movements  to 
remain  regular  in  the  absence  of  all  cerebral  guidance. 
Setting  out  from  Limoges  with  a  friend  in  a  rowing  boat, 
we  descended  the  Vienne  to  the  Loire,  and  down  the 
Loire  to  its  mouth.  Rowing  was  a  sufficiently  familiar 
exercise  to  us  to  be  performed  without  any  tension  of  the 
Drain,  and  as  far  as  I  was  concerned  my  mind  was  com- 
pletely freed  from  any  attention  to  changes  of  stroke,  the 
guidance  of  the  boat  being  confided  to  my  friend,  an 
experienced  oarsman. 

We  were  double  sculling.  Many  times  during  the 
twelve  hours  of  each  day's  work  I  completely  forgot  the 
boat  and  the  Vienne  ;  many  times  my  wandering 
imagination  carried   me  a  hundred   leagues   away  from 


388  PHYSIOLOGY    OF    BODILY    EXERCISE. 

my  companion,  the  rhythm  of  my  stroke  being  always, 
however,  in  perfect  unison  with  his.  Our  sculls  always 
carried  back,  and  then  pulled  forwards  through  the 
water,  struck  the  surface  of  the  water  the  same  number 
of  times  per  minute,  always  plunged  to  the  same  depth, 
always  the  same  height  above  the  water  in  the  backward 
movemicnt  of  the  sculls. 

I  several  times  tried  to  ascertain  if  this  perfect  agree- 
ment were  not  due  to  the  more  sustained  attention  of  my 
companion  who  could  have,  scullmg  bow,  made  his  move- 
ments follow  mine,  increasing  or  diminishing  the  fre- 
quency of  his  stroke  according  to  mine.  But  closer 
examination  showed  that  it  was  really  the  constant 
uniformity  of  our  movements  which  ensured  their  agree- 
ment. In  fact  many  times  we  separately  counted  the 
frequency  of  our  strokes,  and  while  we  were  attending  to 
them,  during  serious  conversation,  animated  discussion, 
or  profound  reverie,  the  result  of  our  obervations  was 
always  the  same  :  nineteen  strokes  per  minute. 

Thus,  after  a  certain  time,  this  exercise  of  rowing,  which 
had  been  very  laborious  to  learn,  had  become  as  it  were, 
stereotyped  in  the  motor  organs,  and  was  performed 
automatically.  Further,  during  the  whole  voyage,  the 
pace  we  had  adopted  at  the  outset  was  maintained  with- 
out change.  Every  morning  of  the  nine  days  which  the 
journey  lasted,  the  muscles  resumed  their  regular  move- 
ment of  the  evening  before,  contracting  nineteen  times 
per  minute  with  the  regularity  of  a  clock,  without  any 
intervention  of  the  conscious  faculties.  Our  "stroke" 
had  become  automatic. 

Thus  the  brain,  the  organ  of  thought,  can  cease  to 
preside  over  a  movement  without  the  latter  losing  its 
regularity  and  precision.  When  a  movement  has  often 
been  repeated  it  seems  that  the  spinal  cord  retains  its 
form  and  mode  of  performance,  as  the  brain  retains  the 
sound  of  the  articulation  of  words.  How  can  a  compli- 
cated movement,  like  that  of  rowing,  be  thus  impressed 
on  the  spinal  cord  ?  It  is  difficult  to  say  :  but  who  can 
say  how  words,  phrases,  entire  pages,  are  written  in  the 
brain,  and  how  is  it  that  we  are  able  to  repeat,  without  a 


AUTOMATISM     IN     EXERCISE.  389 

sinc^le  mistake,  long  passages  of  verse  learned  more  than 
thirty  years  before? 

We  must  then  be  content  to  accept  the  well-established 
fact,  and  to  draw  from  it  legitimate  conclusions.  We 
cannot  refuse  to  admit  that  the  spinal  cord  has  a 
memory.  This  organ,  which  is  primitively  a  conductor 
of  movements  initiated  by  the  brain,  remembers  these 
movements  and  can  repeat  them  under  certain  conditions, 
without  the  will  intervening  otherwise  than  to  open  and 
to  close  the  series  of  movements.  The  memory  of  the 
spinal  cord  has  for  its  result  the  persistence  in  an  auto- 
matic condition  of  a  movement  often  practised. 

But  the  spinal  cord  does  not  merely  keep  the  remem- 
brance of  the  frequency  of  an  often-repeated  action  ;  it 
also  preserves  faithfully  the  memory  of  the  measure,  the 
rhythm  and  the  speed  with  which  it  is  performed.  It  is 
from  this  persistence  of  impressions  in  the  nervous 
s)^stem  due  to  an  often-repeated  action,  that  the 
habitually  slow  or  fast  gait  of  each  individual  results. 

We  become  accustomed  alike  to  slowness  and  to 
vivacity  of  movements,  and  often  both  the  speed  and 
the  heaviness  of  tread  are  the  result  of  a  habit  con- 
tracted in  childhood  of  which  we  do  not  find  it  easy  to 
free  ourselves. 

Automatism  marks  with  an  indelible  seal  the  first 
muscular  actions  performed,  as  memory  stamps  in  a 
young  brain  the  first  phrases  learned  by  heart. 

W^hen  a  horse  has  begun  to  gallop  slowly  it  is  difficult 
afterwards  to  urge  it  to  more  rapid  movement.  In  the 
great  racing  stables  they  use  very  young  boys,  who 
can  ride  sufficiently  well,  in  training  horses.  With  this 
light  burthen  the  horse  can  be  urged,  at  the  first  gallop, 
to  a  pace  which  would  be  impossible  if  it  had  a  man  on 
its  back,  instead  of  a  child.  Trainers  attach  great  im- 
portance to  these  early  habits  of  movement,  and  we  have 
heard  a  most  experienced  racing-man  deplore  the  im- 
possibility of  procuring  in  the  country  these  boys  as 
light  as  monkeys.  Under  them  the  horse  acquires  the 
habit  of  a  gallop  which  discomforts  and  discourages,  at 


590  PHYSIOLOGY    OF    BODILY    EXERCISE. 

the  very  outset  of  the  race,  horses  which  have  been 
trained  to  a  slower  movement. 

Fencers,  says  Bazancourt,  will  never  have  quickness  in 
fencing  if  they  wait  too  long  to  regulate  their  move- 
ments, for  this  makes  their  hands  slow. 

It  needs  an  effort  of  will  to  oppose  an  action  which 
has  become  unconscious  and  to  change  an  acquired 
pace.  If  the  muscles  are  abandoned  to  their  mechanical 
impulse,  they  always  return  to  the  rhythm  which  is 
provided  for  them  automatically.  The  horse  early  accus- 
tomed to  a  slow  movement  makes  a  supplementary 
expenditure  of  nervous  energy  when  we  wish  to  hasten 
its  normal  gallop  ;  and  we  must  not  attribute  the  in- 
creased fatigue  solely  to  the  increased  work  needed  to 
gallop  faster.  In  fact  the  animal  would  also  experience 
this  nervous  discomfort  due  to  the  effort  needed  for  an 
unusual  co-ordination  of  movement,  if  compelled  to 
slacken  its  gallop  much  below  the  normal. 

In  this  manner  we  can  explain  the  fatigue  experienced 
by  a  man  used  to  walk  fast,  when  he  is  obliged  to 
accommodate  his  pace  to  that  of  a  slow  walker.  The 
discomfort  felt  either  on  exceeding  or  falling  below  our 
ordinary  pace  are  alike  due  to  the  intervention  of  an 
effort  of  new  co-ordination  in  order  to  adapt  to  an 
abnormal  rhythm  the  movements  which  are  ordinarily 
performed  mechanically,  without  the  intervention  of  the 
guiding  faculties. 

IL 

When  a  man  performs  an  automatic  movement  he. 
makes  a  call  upon  the  memory  of  his  spinal  cord  and 
distracts  his  attention  from  the  work.  When,  on  the 
contrary,  the  movement  is  new  to  him,  or  difficult,  or 
demands  a  violent  effort,  the  conscious  faculties  are 
obliged  to  enter  into  energetic  action  ;  the  muscular 
sense  gives  precise  indications  of  the  degree  of  contrac- 
tion which  must  be  given  to  the  muscles  ;  the  faculties 
which  preside  over  comparison  and  judgment  appreciate 
what  must  be  added  to  or  substracted  from  the  muscular 


AUTOMATISM    IN     EXERCISE.  39 1 

efToit,  to  give  perfect  precision  to  the  movement;  finally, 
the  will  comes  into  play  to  give  the  definite  impulse  to 
muscular  activity.  These  are  so  many  factors  which 
increase  the  expenditure  of  nervous  energy  without 
making  the  muscle  perform  any  more  work. 

Automatism  in  m.ovements  economises  work  of  the 
brain,  as  memory  economises  mental  work.  There  are 
formulae  which  shorten  mathematical  work,  by  enabling 
us  to  dispense  with  several  elementary  operations. 
Similarl}-,  by  a  series  of  automatic  movements  we  are 
able  to  dispense  with  the  attentive  coordination  of  each 
muscular  action  of  which  the  spinal  cord  has  preserved, 
so  to  speak,  the  formxula. 

If  we  now  enter  upon  the  practical  application  of  the 
physiological  facts  we  have  just  been  discussing,  we  sea 
at  the  first  glance  the  great  hygienic  superiority  of 
exercises  which  can  be  performed  automatically. 
Economy  of  nervous  energy,  complete  repose  of  the 
brain,  absolute  inaction  of  the  psychical  faculties,  such 
are  the  conditions  in  which  automatic  exercise  is  per- 
formed. The  work  of  the  human  system  is  then  per- 
formed by  the  coarser  parts  of  the  machine,  and  fatigue 
is  first  felt  by  the  subordinate  agents  of  movement.  The 
nerve-centres,  having  taken  no  part  in  the  work,  do  not 
suffer  from  the  discomforts  which  follow  it.  Fatigue, 
after  automatic  exercises,  is  purely  muscular  :  it  rather 
affects  the  body  and  limbs  than  the  head  and  the  nerves. 

Hence  it  is  not  difficult  to  understand  the  immense 
advantage  presented  by  automatic  exercises  when  we 
seek  in  muscular  work  a  derivative  for  brains  fatigued  by 
intellectual  overwork. 

We  have  so  far  endeavoured  to  establish  scientifically, 
nn  a  physiological  basis,  the  peculiar  characters  which 
differentiate  the  exercises  in  which  the  brain  is  not  con- 
cerned from  those  which  need  an  effort  of  will  and  a 
work  of  co-ordination.  It  remains  for  us  to  fortify  our 
theoretical  deductions  by  the  observation  of  facts,  and 
for  this  it  is  necessary  to  appeal  to  the  experiences  of  all 
those  who  have  practised  bodily  exercises. 


392  PHYSIOLOGY    OF    BODILY    EXERCISE. 

There  is  nothing  which  recalls  the  fatigue  produced  by 
learning  a  difficult  exercise  so  much  as  that  which  accom- 
panics  the  laborious  solution  of  a  difficult  problem. 
There  is  the  same  strained  effort  of  attention  during  the 
work,  there  is  the  same  cerebral  prostration  afterwards. 
In  both  cases  the  fatigued  man  refers  the  seat  of  his 
discomfort  to  his  head.  This  is  because  in  both  cases 
the  brain  has  been  at  work. 

A  man  must  be  a  poor  observer  if  he  has  failed  to 
notice  the  instinctive  repugnance  which  is  felt  for 
difficult  exercises  by  all  persons  suffering  from  mental 
overwork. 

Look  at  a  schoolboy  before  a  master  teaching  him  the 
first  elements  of  fencing.  His  sullen  and  cross  ex- 
pression, indicating  fatigue  and  weariness,  seems  to 
say  :  "  This  is  worse  than  construing  !  "  Let  the  same 
boy  out  of  school  into  the  fields  and  you  will  see  him 
start  like  an  arrow,  his  legs  carrying  him  away  in  a  lively 
run.  He  will  in  a  few  minutes  do  ten  times  as  much 
work  as  he  would  in  fencing  practice,  but  this  work  is  an 
affair  of  the  legs  :  his  head  is  not  concerned  in  it.  He 
will  come  back  very  hot  and  breathless,  bathed  in  sweat, 
but  his  mind  will  be  freed  and  his  brain  rested. 

Remember  your  own  college  days.  Who  were  the 
young  men  who  were  most  ardent  in  physical  exercises, 
the  greatest  lovers  of  the  trapeze,  the  prize  winners  in 
the  gymnasium  ?  Those  whose  intellectual  faculties  had 
escaped  overwork  on  account  of  their  idleness, those  whose 
cerebral  nervous  force  was  not  expended  over  books,- 
which  were  indeed  open  before  them,  but  which  they  did 
not  read. 

If  opposed  observations  are  quoted  they  refer  to 
persons  equally  well  endowed  in  the  matter  of  brain  and 
muscle,  and  who  have  as  much  ease  in  mental  work  as 
fitness  for  bodily  exercises.     These  are  rare  exceptions. 

There  is  a  general  tendency  to  blame  the  indolence 
and  physical  apathy  manifested  by  students  whose 
more  serious  studies  demand  a  greater  strain  of  the 
intellectual  faculties.  They  are  told  it  would  be 
better  for  them  if  they  used  otherwise  than  in  conversa- 


AUTOMATISM    OF    EXERCISE.  393 

tîons  and  reveries,  the  time  which  is  given,  grudgingly 
enough,  for  the  recreation  of  their  overtasked  brains. 
Their  masters  scold  them,  and  stimulate  them  to  arise 
from  this  far  iiiente  to  perform  some  violent  exercise. 
All  the  apparatus  in  the  gymnasium  are  at  their  dis- 
posal :  why  do  they  not  make  use  of  them  ? 

In  spite  of  the  master's  exhortations,  the  pupil  whose 
head  has  done  much  work  feels  little  disposed  to  bring 
his  limbs  into  action,  and  he  avoids  with  an  instinctive 
repugnance  the  trapeze  and  the  horizontal  bar.  Is  this 
then,  as  is  often  said,  because  he  disdains  an  exercise 
too  childish  for  the  dignity  of  his  fifteen  years  ?  Is  it 
not  rather  because  he  fails  to  find  in  muscular  fatigue 
the  pretended  derivative  able  to  bring  rest  to  his  spirit  ? 

For  us,  if  the  child  suffering  from  mental  overwork 
does  not  feel  any  desire  for  bodily  exercise,  it  is  because 
his  instinct  is  sounder  than  the  opinion  of  his  masters  :  it 
is  because  the  gymnastics  to  which  he  is  urged  would 
need  an  effort,  not  only  of  his  muscles,  but  of  his  brain, 
already  wearied  by  study. 

The  importance  of  care  in  the  choice  of  an  exercise 
from  the  point  of  view  of  cerebral  hygiene  has  not 
hitherto  been  recognized,  and  people  have  not  thought  of 
availing  themselves  of  the  great  advantage  to  be  derived 
from  easy  exercises. 

This  advantage  may  be  summed  up  in  two  words  ; 
they  produce  7m{scular  Ï3itigue  without  leading  to  nervous 
fatigue.  They  quicken  the  blood  current,  make  the 
breathing  more  active,  regulate  the  digestive  functions, 
without  at  the  same  time  needing  that  excessive  activity 
of  the  cerebral  functions  which  always  accompanies  diffi- 
cult exercises. 

No  one  has  hitherto,  however,  thought  of  using  these 
precious  advantages.  No  one  even  takes  into  account 
tlie  conditions  which  may  make  the  degree  of  difficulty  of 
an  exercise  vary.  No  difference  is  made,  in  the  hygienic 
application  of  bodily  exercises,  between  those  which  are 
new,  and  those  which  a  man  has  long  practised  ;  the 
cerebral  work  demanded  during  the  period  of  apprentice- 
ship of  an  unknown  movement  is  not  taken  into  account 


394  PHYSIOLOGY    OF    BODILY    EXERCISE. 

After  a  certain  period  of  study,  difficult  exercises 
have  been  learned,  and  may  then  become  automatic. 
Their  effects  will  then  be  very  different.  Is  it  not  quite 
a  different  thing  to  amitse  oneself  with  dancing,  from 
occupying  oneself  with  learning  dancing?  Dancing, 
riding,  rowing,  even  running,  when  they  have  long  been 
practised,  need  no  more  brain  work  than  walking,  which 
is  above  all  an  automatic  exercise. 

But  for  certain  bodily  exercises  the  period  of  ap- 
prenticeship is  indefinitely  prolonged,  and  the  move- 
ments need  an  unceasing  guidance  on  the  part  of  the 
nerve-centres  and  the  conscious  faculties,  because  these 
movements  cannot  be  constantly  identical,  and  unfore- 
seen emergencies  occur.  Fencing  can  never  become  an 
automatic  exercise,  notwithstanding  the  tendency  ex- 
hibited by  certain  parries  and  thrusts  to  become  habitual 
actions  and  to  be  performed  instinctively  ;  the  move- 
ments cannot  always  be  performed  in  the  same  manner 
and  follow  always  the  same  order,  for  they  are  subordi- 
nated to  those  of  the  opponent.  Riding  becomes  an  auto- 
matic exercise  if  it  is  always  practised  on  the  same  horse, 
to  which  the  rider  accommodates  his  movements.  It  needs 
on  the  other  hand  the  activity  of  the  brain,  and  demands 
a  very  attentive  work  of  coordination,  in  cases  in  which 
very  difficult  horses  are  ridden,  which  differ  very  much 
in  character  and  obedience. 

We  cannot  then  res^ard  automatism  as  a  character 
which  will  serve  to  mark  off  a  particular  group  of  exer- 
cises. It  is  rather  a  mode  of  performance  which  most 
known  exercises  may  assume,  when  these  exercises  are 
performed  under  conditions  which  we  have  endeavoured 
to  determine  in  this  chapter. 

To  sum  up,  muscular  automatism  is  a  function  de- 
volved on  the  more  dependent  parts  of  the  nervouf; 
system,  with  the  object  of  economising  the  work  of  thii 
brain,  considered  as  the  guiding  force  of  the  human 
machine. 

Hitherto  people  have  not  sufficiently  considered,  in 
the  various  gymnastic  exercises,  the  importance  of  this 
economy  from  the  standpoint  of  hygiene  of  the  nervous 


AUTOMATISM    IN     EXERCISE.  395 

system.  They  have  not  yet  estabh'shed  the  very  different 
indications  for  exercises  which  make  the  nerve-centres 
do  much  work,  and  for  those  which  demand  but  Httle 
action  of  the  brain. 

These  indications  are  however  very  formal  and  clear, 
and  may  thus  be  shortly  expressed  : — 

Whenever  the  therapeutical  application  of  exercise 
has  for  its  aim  a  lively  stimulation  of  the  nerve-centres 
and  the  performance  of  brain  work,  difficult  exercises  are 
to  be  preferred  to  automatic  exercises. 

Easy,  instinctive  exercises,  or  those  which  have  become 
familiar  throui^h  long  practice,  those  in  a  word  which 
can  be  performed  automatically  without  needing  any 
sustained  effort  of  attention,  are  suitable,  on  the  contrary, 
for  persons  whose  brains  must  be  spared  while  their 
muscles  are  being  fatigued. 

Prescribe  fencing,  gymnastics  with  apparatus,  and 
lessons  in  a  riding  school  to  all  those  idle  persons  whose 
brain  languishes  for  want  of  work.  The  effort  of  will 
and  the  work  of  coordination  which  these  exercises 
demand  will  give  a  salutary  stimulus  to  the  torpid  cere- 
bral cells.  But  for  a  child  overworked  at  school,  for 
a  person  whose  nerve-centres  are  congested  owing  to 
persistent  mental  effort  in  preparing  for  an  examination, 
for  such  we  must  prescribe  long  walks,  the  easily  learned 
exercise  of  rowing,  and,  failing  better,  the  old  game 
of  leap-frog  and  prisoner's  base,  running  games,  any- 
thing in  fact  rather  than  difficult  exercises  and  acrobatic 
gymnastics. 


Date  Due 


^'CM 


4  1945 


m  1 9  ^^> 

JCTl  5  1! 


Ù  i:3Hr\ 


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PA781 
Lagrange 
Physiology  of  bodily  exercise 


L13 


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THE 


^^0^^ 


SCIENTIFIC  SERIES 


